Difference between revisions of "CudaText"

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* VSCode has the add-on "Macros", with it you need to create/configure command sequences by hands. Not simple task. CudaText has the plugin "Macros" and it records usual keypresses. Much eaiser to do.
* VSCode has the add-on "Macros", with it you need to create/configure command sequences by hands. Not simple task. CudaText has the plugin "Macros" and it records usual keypresses. Much eaiser to do.
* CudaText gives [[#File_viewer|viewer for files of unlimited size]].
* CudaText gives [[#File_viewer|viewer for files of unlimited size]].
* CudaText gives option "caret_proximity_vert" to set minimal distance of caret to top/bottom edge.
* CudaText plugins API is simpler.
* CudaText plugins are easier to write (Python API is simpler).
* CudaText supports UTF-32 LE/BE encoding.
* CudaText supports UTF-32 LE/BE encoding.

Revision as of 19:04, 6 July 2022


CudaText is a cross-platform text editor, written in Lazarus.

  • Syntax highlighting for a lot of languages: 270+ lexers
  • Code folding
  • Code-tree (list of functions/classes/etc, if lexer supports this)
  • Multi-carets, multi-selections
  • Search/replace with regular expressions
  • Support for many encodings
  • Extendable by Python add-ons
  • Command palette
  • Configs in JSON files
  • Interface and syntax themes
  • Based on the ATSynEdit engine

Features for HTML/CSS coding:

  • Built-in HTML and CSS auto-completion
  • HTML tags completion with Tab-key
  • HTML color code underlining
  • HTML tooltips on mouse-over
  • Viewer for picture files (jpeg, png, gif, bmp, ico, webp)

Screenshot on Windows:


Disadvantages compared to Sublime Text / VSCode

  • CudaText doesn't use 3D acceleration on rendering, so it may lag (and/or consume lot of CPU) if you scroll text, with big window size (not on Windows, Windows API works fast enough).
  • CudaText doesn't provide "Go to anything" command, instead it gives several separate commands:
    • Go to line number,
    • Go to project file,
    • Go to bookmark,
    • Go to code-tree symbol, ...
  • CudaText lexers are "simple": they don't parse text as deeply as ST/VSCode; so you need the LSP plugin if you need IntelliSense features.
  • CudaText key bindings are simpler: commands don't have "arguments" and cannot be set per-project (but can be set per-lexer).

Advantages over Sublime Text 3

Advantages over Visual Studio Code

  • VSCode has the option "maximal count of ui-tabs", because its ui-tabs are memory hungry. CudaText allows to open 1000+ ui-tabs without problems.
  • VSCode is slow for file sizes 10M...100M, while CudaText allows this without problems. For size 2M+ CudaText disables lexers, but "lite lexers" (Log, XML, JSON) work always.
  • VSCode doesn't have customizable toolbar.
  • VSCode doesn't allow to show side-panels in floating (detached) window.
  • VSCode has internal "find in files" but CudaText has FindInFiles-4 plugin with much more features.
  • VSCode cannot show inter-line gaps with pictures. CudaText plugin "Insert Pics" is based on this feature.
  • VSCode doesn't have the analog of CudaText "Color Text" plugin (not 100% sure here).
  • VSCode doesn't have the analog of CudaText "Draw Lines" plugin.
  • VSCode cannot place text caret beyond end-of-line (not 100% sure here).
  • VSCode has the add-on "Macros", with it you need to create/configure command sequences by hands. Not simple task. CudaText has the plugin "Macros" and it records usual keypresses. Much eaiser to do.
  • CudaText gives viewer for files of unlimited size.
  • CudaText plugins API is simpler.
  • CudaText supports UTF-32 LE/BE encoding.



CudaText has configuration system in JSON files: call menu item "Options / Settings - default" and you'll see the default config. You should copy lines from this file to the file from "Options / Settings - user" and edit this user config - this is the actual config file. Default config is not read by CudaText, it's only to show possible options.

You can copy JSON comments too. In the user config, include useful lines in the curly braces "{ }", this is JSON format. Trailing comma before "}" is allowed here.

User config
File "settings/user.json". Can be opened via menu item "Options / Settings-user".
Default config
File "settings_default/default.json". Can be opened via menu item "Options / Settings-default". CudaText doesn't use this file, it's only for user reference. CudaText only opens this file by the command, and this file is parsed by plugin "Options Editor".
Lexer specific configs
Files "settings/lexer NNN.json". It is layer which is read after user config, when user activates some lexer. E.g. if you open C file, config file "lexer C.json" is read. You should not write "ui_" options to lexer specific configs (it may give weird effects on changing lexer), and some other global options.
  • For (None) lexer, config file is named "lexer -.json".
  • For lite lexers, config files are named with suffix, e.g. "lexer XML ^.json".
Default lexer specific configs
Files "settings_default/lexer NNN.json". It is layer which is read after user config, but before lexer specific config. CudaText provides several such files, with useful defaults.
Hotkeys config
File "settings/keys.json". Special dialog allows to change all hotkeys in CudaText. You should not edit this config file. Dialog is called from "Help / Command palette" by F9. Dialog allows to set 1st and 2nd hotkeys for any command (except dynamically added commands to change lexer).
Plugin configs
Files "settings/cuda_*". Plugins store their settings in there, and files can be in any format (most used are JSON and INI). Good quality plugins provide menu items in "Options / Settings-plugins" to open their config file, or to show configuration dialog.
History files
Files "settings/history*.json". Don't edit them. Mentioned here because sometimes users need to delete their history files (dialog positions, recent files list etc, recent search strings etc).

File types config

Section "detect" in user.json. Specifies mapping from "file name" to "lexer name".

  "detect": {
    "*.mht": "HTML",
    "myconfig.conf": "Nginx",
    ".profile": "Bash script",
  • Key name: File mask. Must be full name without path, or extension with leading "*." like "*.ext", or double extension like "*.ext1.ext2". More complex masks are not yet supported.
  • Key value: Lexer name. Value "-" means "don't activate lexer".

Another method to specify this mapping is dialog "Lexer properties", in which you can add extension or name+extension to a lexer. But dialog is more limited: it saves option to the lexer file (data/lexlib/lexername.lcf), so setting will be reset on reinstalling lexer.

Detection by first file line

Section "detect_line" in user.json. Allows to detect lexer by first line of file.

  "detect_line": {
    "<html.*": "HTML",
    "<!DOCTYPE.*": "HTML",
    "<\\?xml.*": "XML",
  • Key name: Reg-ex for the first file line. Case sensitive, but you can use (?i) modifier in reg-ex. Note that this is a reg-ex, using syntax similar to Perl reg-ex, so for example "#" char must be escaped with a backslash, and instead of file-mask "*" you must write ".*". Also note that current implemenation cannot handle forward slashes "/" good, so escape these slashes or use "." instead of them.
  • Key value: Lexer name. Value "-" means "don't activate lexer".

CudaText has several default values:

  • "<\?xml .+": "XML"
  • "\#!\/bin\/(ba)?sh": "Bash script"
  • "\#!\/usr\/bin\/env (ba)?sh": "Bash script"
  • "\#!\/usr\/bin\/env python\d*": "Python"

Grouping in Plugins menu

Section "plugin_groups" in user.json. Configures grouping in the Plugins menu, e.g. allows to put all "HTML ..." and "CSS ..." menu items into "Web" submenu. Example:

  "plugin_groups": {
    "CSS .+": "Web",
    "HTML .+": "Web",
    "JS .+": "Web",
    "Config.+": "Config",
    "Option.+": "Config",
  • Key name: regular expression for the first part of menu name. E.g. if menu name in install.inf is "CSS Utils\Misc\Action", then first part is "CSS Utils".
  • Key value: group name, it can be with "\" char to make several levels.

Help topics

Command line parameters


cudatext [ key ... ] filename ...

Supported keys:

  • -h, --help - Show command-line help and exit.
  • -v, --version - Show application version and exit.
  • -z=value - Open files from command-line in internal viewer, using given viewer mode:
    • -z=text - Text mode with variable line length, single-byte encodings
    • -z=binary - Text mode with fixed line length, single-byte encodings
    • -z=hex - Hexadecimal mode, single-byte encodings
    • -z=unicode - Text mode with variable line length, UTF-16 LE/BE encodings
    • -z=uhex - Hexadecimal mode, UTF-16 LE/BE encodings
  • -r - Open files from command-line in read-only mode.
  • -e=value - Open all files from command-line in given encoding.
  • -el - Show possible encoding names and exit.
  • -n - Ignore option "ui_one_instance", and open new app window.
  • -nsl - Don't load last session on start.
  • -nss - Don't save last session on exit.
  • -ns - Shortcut to "-nsl" together with "-nss".
  • -nh - Don't load saved file history (caret, selection, scroll position, etc).
  • -nn - Don't suggest to create new file if command-line filename is not found.
  • -s=folder - Specify full path of the "settings" folder, which contains all configuration files.
  • -i - Read the contents of stdin to a new document. Unix only. It can be used in Unix shell like: "ls -l | cudatext -i".
  • -id=name - Set "group" for single-instance mode, so that program with one "group" will not interfere and find instances with another "group". Unix only. Default value is "cudatext.0".
  • -w=left,top,width,height - Set position/size of the main window. Up to 4 numbers should be specified, any number can be skipped to keep previous value.
  • -c=cuda_module,method_name - Run the specified command plugin on startup. It runs the command plugin for the currently active editor tab, so make sure you don't pass multiple filenames in the command line, and current session doesn't have multiple files. So, it is good to use together with "-n" and/or "-ns" params. How to know the "cuda_module"? It is the name of subfolder under "py" folder. How to know "method_name"? It is the value of "method=" key in the "py/cuda_module/install.inf" file.
  • -p=cuda_module#param1#param2... - Run the specified plugin, and pass to its "on_cli" event specified param strings. Count of params must be expected by plugin, e.g. Differ plugin supports "on_cli" and expects 2 filenames. If params contain spaces, you must double-quote the part of the command-line beginning with -p: "-p=......".


  • Filenames can be with ":line" or ":line:column" suffix to place caret.
  • Folders can be specified too. They will be opened as a "project" in the Project Manager.
  • Project files (.cuda-proj) can be loaded.
  • Session files (.cuda-session) can be loaded, if Session Manager installed.
  • Non-existing file name can be specified, program will ask to create it.
  • File masks with "*" symbol are supported, e.g. command "cudatext test/t*.htm*" will work.


On macOS you cannot run "cudatext", but you can open Terminal and create the alias for "cudatext":

alias cudatext=open\ /Applications/CudaText.app\ --args

This allows to open in Terminal commands like "cudatext ~/filename.html".

Mouse shortcuts

Note for macOS: use Command key instead of Ctrl key, in all the mouse shortcuts listed here.


  • Ctrl+click - Add/remove caret.
  • Ctrl+wheel click - Add/remove caret.
  • Ctrl+drag - Add caret with selection.
  • Ctrl+Shift+click - Add column of vertically aligned carets, from previous caret position to the clicked line.


  • Alt+drag - Make column selection. See #Behaviour of column selection.
  • drag on gutter's line numbers - Select text by entire lines.
  • double-click and immediately drag - Select text by words.


  • double-click - Select clicked word. See the option "nonword_chars".
  • triple-click - Select entire line (block is limited by newline characters).
  • wheel click - Configurable by option "mouse_middle_click", choices are:
    • Start "browser scrolling" mode: circle mark appears and mouse moving around this mark auto-scrolls text in 4 directions; speed of scrolling depends on distance of cursor from circle mark (any click to turn off).
    • Paste from clipboard. This mimics Linux apps behaviour. With this choice, it's good to install plugin "Auto-Copy to Clipboard".
    • Call "Go to definition" command.
    • Nothing.
  • click on Extra1/Extra2 mouse buttons - these clicks do nothing by default, but they produce keyboard actions BrowserBack/BrowserForward (extended keys on Windows keyboards), and so they can be assigned in the hotkeys setup dialog (F9 in the Command Palette). For example, Ctrl+Extra1 produces Ctrl+BrowserBack keyboard action.


  • Shift+Alt+click - Make vertical (column) selection, from the first caret to the clicked position.
  • Shift+ scroll mouse wheel - Scroll text horizontally.
  • Ctrl+ scroll mouse wheel (with option "mouse_wheel_zoom":true) - Zoom text in/out.
  • Ctrl+ scroll mouse wheel (in the picture viewer) - Zoom picture in/out.

Drag-drop of selected text block:

  • Dragging inside single document: if Ctrl is pressed during the drop (you should press Ctrl after dragging is started), block will be copied (not moved) to the pointed position.
  • Dragging to a different document (see #Groups of tabs): if Ctrl is pressed during the drop, block will be moved (otherwise it will be copied).

Command "Go to definition" can be called by different mouse shortcuts: by Ctrl+Alt+click (default), Alt+click, etc, this depends on option "mouse_goto_definition".


Multi-carets are several carets at once. All carets work together for many editing commands: caret moving, text typing, deleting, selection with keyboard. See "Mouse shortcuts", how to add/remove carets.




If you add caret with Ctrl+click, caret has no selection. If you add caret with Ctrl+drag, caret will have selection. You can add selections to carets later, by Shift+arrows, Shift+Home, Shift+End etc.

Multi-selections are handled specially on copy/paste. If you copy selections, then move carets, then paste, paste will insert clipboard lines into carets: line-1 at caret-1, line-2 at caret-2 etc (only if carets count equals to lines count in clipboard, otherwise result is different).

Animation shows this:


Commands with selections

Clipboard commands work with multi-carets and multi-selections the special way. Also "Delete char" commands (Delete/Backspace keys) works the special way.

Command Behaviour, when there're no selections Behaviour, when at least one selection present
Copy to clipboard Copies entire lines, containing carets. Ignores multiple carets on a same line. Copies only selections text. Ignores carets without selections.
Cut to clipboard Similarly to "Copy" without selections. Similarly to "Copy" with selections.
Paste from clipboard First, selections are cleared (deleted). Then, command pastes text into each caret position. Special case is when clipboard lines count equals to carets count - in this case, first line is inserted at first caret, second line is inserted at 2nd caret, etc.
Delete char left (Backspace) / Delete char right Deletes one char at each caret position. Deletes only selections text. Ignores carets without selections.


Syntax highlighters in CudaText are called lexers. Lexers are compatible with SynWrite editor (which is frozen). Lexer engine by EControl.ru is used, with modifications by Alexey Torgashin. Main modification is support for folding in Python and other syntaxes with indentation-based folding. Other modifications are porting from Delphi to Free Pascal and optimizations. EControl.ru's original lexer engine is closed source, but CudaText's version is open source, with the permission from EControl.ru.

  • Dialog "Lexer properties" allows to config props of current lexer (selected via statusbar panel in CudaText). You can config: lexer name, file types, commenting for language, colors of tokens, font-styles (bold/italic/underline), borders around tokens.
  • Dialog "Lexer library" shows list of installed lexers. Dialog shows lexers which are in the folder "data/lexlib".


Dialog "Lexer library" has hotkeys:

  • Enter: same as "Configure" button
  • Delete: same as "Delete" button
  • Space: same as "Hide/Show" button
  • Esc: close dialog

Lexers on SourceForge

Preinstalled lexer library has limited set of lexers. All other lexers are hosted on CudaText.SF.net. You can download the entire add-ons pack too.

To install "lexer.*.zip" (or any add-on ZIP file) in CudaText: open this ZIP file via "File / Open", CudaText will suggest to install it.


List of lexers

The following lexers (counting only important ones) exist for SynWrite and CudaText. Most of them are located in the Addons Manager "Install" list.

  • 1C
  • ABAP
  • Abaqus Keywords
  • ABC Notation
  • ActionScript
  • Acu Cobol
  • Ada
  • Adobe Flash
  • Amazon Ion
  • AMPL
  • AngelScript
  • Apache config
  • Apache Hive
  • Apache Pig
  • AppleScript
  • Arduino
  • AsciiDoc
  • Assembly
  • Assembly ARM
  • Assembly AVR
  • Assembly FASM
  • Assembly GNU
  • Assembly JWASM
  • Assembly MASM x86
  • Assembly MIPS
  • Assembly Motorola 68k
  • Assembly NASM x86
  • Assembly PowerPC
  • Assembly RISC-V
  • Assembly SHARC DSP
  • Assembly SPARC
  • Assembly STM32
  • Assembly Z80 SjASM
  • Assembly Z80 RGBDS
  • Astro
  • Asymptote
  • Autoconf M4
  • AutoHotkey
  • AutoIt
  • Automake
  • Automation Basic (B&R Automation Studio)
  • AviSynth
  • AWK
  • Ballerina
  • Bash script
  • Batch files
  • BibTeX
  • Bicep
  • Bitsquid SJSON
  • Bohemia SQF
  • Boo
  • Brainfuck
  • C
  • C#
  • C++
  • Caffe Prototxt
  • Clarion
  • Clavier
  • Clipper
  • Clojure
  • CMake
  • Cobol
  • CodeVisionAVR
  • CoffeeScript
  • ColdFusion
  • Coq
  • CRF files
  • Crystal
  • CSS
  • CUDA C++
  • Cython
  • D
  • Dalvik bytecode (Smali)
  • Dart
  • Delphi resources
  • Dhall
  • Diff
  • Dockerfile
  • DotENV
  • Eiffel
  • Elixir
  • Elm
  • Erlang
  • etlua Template
  • Euphoria
  • F#
  • Factor
  • Falcon
  • Fish
  • Forth
  • Fortran
  • FoxPro
  • FreeBASIC
  • G-code
  • GAMS
  • GDScript
  • Gemini (web pages)
  • Gherkin (Cucumber; Behat)
  • GHS.com MULTI IDE (3 lexers)
  • GLSL
  • GNU linker
  • Gnuplot
  • Go
  • Gold Parser
  • Grails Server Pages (GSP)
  • Graphviz DOT
  • GraphQL
  • Great Cow Basic
  • Groovy (Gradle)
  • Grub4Dos
  • Haml
  • Harbour
  • Hare
  • Haskell
  • Haxe
  • HLSL
  • HTML
  • HTML Diafan
  • HTML Django DTL
  • HTML Embedded JS
  • HTML Handlebars
  • HTML Laravel Blade
  • HTML Liquid
  • HTML Mustache
  • HTML Ruby-ERB
  • HTML Smarty
  • IDL files
  • IDL language
  • Informix 4GL
  • Ini files
  • Inno Setup
  • Intel HEX
  • Jade
  • Jasmine JVM Assembler
  • Java
  • Java Velocity
  • JavaScript
  • JavaScript Babel/ React JSX
  • JCL
  • Jinja2
  • JQ
  • JSON
  • Jsonnet
  • Julia
  • Kivy
  • KiXtart
  • Koka
  • Kontakt Script Processor (KSP)
  • Kotlin
  • LaTeX
  • LESS
  • Lisp
  • LiveCode script
  • Log files
  • Logstash DSL
  • Lola-2
  • Lua
  • Macro Scheduler script
  • Makefile
  • Markdown
  • Maya
  • MediaWiki
  • Meson
  • Metafont
  • MIB files
  • MikroTik Script
  • MiniZinc
  • Modelica
  • Modula-2
  • Modula-3
  • Monkey
  • MSVS Solution
  • MusicBrainz Picard Tagger Script
  • MySQL
  • Nemerle
  • Nginx
  • Nim
  • Nix
  • nnCron
  • NSIS
  • NSL Assembler
  • Oberon
  • Objective-C
  • OCaml
  • OpenCL
  • OpenEdge
  • OpenSCAD
  • Org-mode
  • Papyrus (for Skyrim game)
  • Parser3
  • Pascal
  • Pawn
  • PECmd script
  • Perforce Jam
  • Perl
  • PHP
  • PICL
  • Pike
  • PL/SQL
  • PlantUML
  • Pony
  • PostScript
  • Power Query M
  • PowerShell
  • Prolog
  • Properties
  • Protocol Buffers
  • Pug
  • Puppet
  • PyMOL
  • Pyret
  • Python
  • QML (Qt Modeling Language)
  • R
  • R Markdown
  • Racket
  • Rainmeter
  • Ragel
  • Raku
  • Razor
  • ReasonML
  • Red
  • reStructuredText
  • Rexx
  • RON
  • RPG/IV
  • RTF (RichText)
  • Ruby
  • Rust
  • Sass
  • Scala
  • Scheme
  • Scilab
  • SCSS
  • SFZ Format
  • Singularity
  • Slim
  • Smalltalk
  • Snowflake SQL
  • Solidity (Ethereum)
  • Specman
  • SPICE (PSpice, HSPICE)
  • SPIR
  • SQL
  • Squirrel
  • SRT Subtitles
  • Standard ML
  • Stata
  • Strace
  • Stylus
  • Svelte
  • Swift
  • T-SQL
  • TakeCommand
  • Tcl/Tk
  • Textile
  • TOML
  • Tree
  • Twig
  • TypeScript
  • V
  • Vala
  • VBScript
  • Verilog HDL
  • VHDL
  • VimL (Vimscript)
  • Virgil
  • Visual Basic
  • Visual dBase
  • Vue
  • WikidPad
  • WinBuilder script
  • Windows Resource Script
  • Wolfram
  • WSH script
  • XML
  • XSLT
  • Yacc (Bison)
  • YAML
  • ZenScript (MineTweaker)
  • Zephir
  • Zig

Lexers editing

You can modify/create lexers. But not in CudaText. Install SynWrite (needed Wine on Linux) and in it you have lexer editor dialog.

  • In SynWrite call menu "Options / Addons manager / Install", install needed lexer from web. SynWrite lexer-library must have lexer before you edit it.
  • In SynWrite call "Lexer prop" dialog and edit all you need. Or make new lexer.
  • In SynWrite install "ExLexer" addon. Call it in "Plugins" menu, select needed lexer. You have exported zip file.
  • In CudaText open this zip file. Confirm installation of lexer.

Screenshot of SynWrite dialog:


Lexers editing - styles only

For full-featured lexer editing, you must use SynWrite as described in the topic above. CudaText itself allows to edit only lexer styles, ie colors/ borders/ font-style (bold/italic/strikeout) of lexer styles. How to do that:

  • Activate some lexer for the current document.
  • Call CudaText menu "Options / Lexers / Lexer properties", dialog "Lexer properties" will open.
  • In the "Lexer properties" dialog, activate "Styles" tab, it has UI to customize styles in the active lexer. This UI is enabled only when lexer themes are Off, ie option "ui_lexer_themes":false.

By default that option is On so UI is disabled. If you enable the UI, you can customize all lexer styles. Configuration will be saved to the files "settings/*.cuda-lexops". These files are auto-loaded by CudaText on start.

How to setup styles of hidden sublexer

Some lexers are distributed in packages together with sub-lexer, and sub-lexer is hidden. Example: "HTML Django" with sub-lexer "HTML Django internal" (the second one isn't visible in the Lexers menu, so it's called hidden). Users, which have option "ui_lexer_themes" off, want to configure styles of all lexers. How to access hidden ones?

  • Open "Lexer library" dialog (menu: Options / Lexer / Lexer library).
  • In dialog, focus needed lexer, press "Configure" button
  • Dialog "Lexer properties" will open for selected lexer
  • In dialog's "Styles" tab, configure all you need

You can change visibility of lexer in SynWrite lexer editor (the checkbox will write line "Internal = True" at the end of .lcf file).

How to create distributive of new lexer

In SynWrite, you've created .lcf file in folder SynWrite/Data/LexLib. If you configured "Commenting" options, also file .cuda-lexmap is created. Now you need to create .zip installation of lexer, for both editors: SynWrite, CudaText.

  • In lexer file, replace system colors to usual colors: replace "clWindowText" to "clBlack" (clWindowText may be light on CudaText on Linux); replace "clInfoText" and "clInfoBk" too.
  • In SynWrite, in Addon Manager, install plugin "ExLexer".
  • In SynWrite, run menu item "Plugins / ExLexer", to create .zip for your lexer.
  • In CudaText, open this new zip file, this installs lexer to CudaText.
  • In CudaText, activate your lexer, dialog should show: "Lexer style mapping". Fill items in this dialog.
  • In CudaText, test this "lexer style map" in action: open file with your lexer active, and activate "default" UI theme, then activate "sub" UI theme. Main themes must show nice colors in your syntax file. Call dialog "Options / Lexers / Lexer style mapping" to fix colors.
  • In prev step, you configured .cuda-lexmap file, in folder CudaText/data/lexlib. Copy this file to zip installation of your lexer.
  • Zip must contain: install.inf, .lcf file(s), .cuda-lexmap file per each lexer.

Lite lexers

Lite lexers are lexers is special format (internally it's JSON file), with very limited features. They don't support code-tree, folding, don't support multi-line comments, don't have rich highlighting (e.g. background highlight of string `12+$var` with additional highlight for 12 and $var inside). And they don't keep tokens information in memory (positions of found tokens in text). But they work very fast for any file size (note: lines longer than 4K chars are not parsed). Lite lexers process only lines visible on screen, not all document lines.

Lite lexers have the " ^" suffix in name. Currently few lexers are preinstalled: XML ^, JSON ^, Log files ^, SQL ^. You can also choose them, from the usual lexers menu (they are visible by suffix).

Lite lexers are auto used for big files, if file size is bigger than option "ui_max_size_lexer". And for small files, if normal lexer not found (e.g. "SQL ^" is used also for small files, because "normal" SQL lexer is not preinstalled).

How to change styles in lite lexers? For example, "Log files ^" uses styles "Id"/"Id2", and you want to change that? It's easy:

  • open the file: [CudaText]/data/lexliblite/Log files.cuda-litelexer
  • find and edit styles names
  • all possible styles are listed in the CudaText dialog "Options / Settings - theme - syntax..."

Differences in lexer support in CudaText/SynWrite

  • SynWrite supports "lexer grammar", while CudaText 1.133+ does not support "grammar" anymore.
  • SynWrite lexers need constructs like \x0D\x0A or \z (to catch any line-break: LF, CRLF, CR), while CudaText lexers are OK with simple \n (because internal buffer always has LF separator).
  • Some lexers need to find equal identifiers at begin/end of blocks: HTML, Bash, others. Bash lexer needs extended feature: to see NAME and 'NAME' and "NAME" as equal identifiers (word and quoted word). Only CudaText has this extended feature, not SynWrite.
  • For CudaText you must avoid "system colors" in lexer styles (e.g. "window background", "window text", "hint background"), because OS'es have different system colors.
  • SynWrite lexer settings are not used in CudaText:
    • Option "Restart analysis from the line start" has no effect, it is forced to On in CudaText
    • Default style
    • Selection mark style
    • Search mark style
    • Current line style
    • Collapse mark style
    • Character set
    • Multiline border
    • Options in groups "Syntax tree decoration", "Pen"

How to make editor re-scan entire document on editing

The question makes sense, because when user types the block ending (e.g. "}" in C syntax), editor re-scans the document from the last changed line, and cannot detect that new block is just appeared.

Find the lexer file, .lcf file in the folder data/lexlib. This file has the ending with "end", before "end" you see several lexer settings. You can add there:

FullRefreshSize = 5000

Insert it near the end of file, like here:

  FullRefreshSize = 5000
  LineComment = '#'

This tells lexer to re-scan entire document, on editing in any document place, when document size is less than 5000 chars.

How to support Spell Checker in lexer

Plugin "Spell Checker" checks text, which is inside "strings" and "comments". So you must configure lexer and set there, which lexer elements (tokens) are "strings" and "comments". It is options in the "Lexer properties" dialog of SynWrite, in the "Commenting" tab of dialog. You can change these options without SynWrite too - they are in the data/lexlib/LexerName.cuda-lexmap file, both options are comma-separated names of lexer styles.

For example, let's see XML lexer. We must specify styles:

  • style applied to XML/HTML comments
  • style applied to quoted strings in XML tags
  • style applied to usual text out of angle brackets

If you see lexer config in SynWrite, you will find that we need styles "Comment", "Text" and "Tag val". So we specify in the file data/lexlib/XML.cuda-lexmap:

styles_str=Text,Tag val

Fenced code-blocks


This is the feature of Markdown syntax: fenced code blocks. Blocks begin with:

  • start of line
  • optional spaces
  • 3 or more backtick-chars (also tilde-chars are allowed)
  • optional spaces
  • lexer alias like "cpp" or "cs"
  • optional spaces
  • end of line.

Blocks end with:

  • start of line
  • optional spaces
  • 3 or more backtick-chars (also tilde-chars are allowed)
  • optional spaces
  • end of line.

The beginning and ending sequences are tokenized as single token.

CudaText has the file which lists the supported lexer aliases: data/lexlib/aliases.ini. The file was compiled from this document. Lexer alias will be resolved to the actual lexer name, only if that lexer is installed, otherwise you won't see an error, but block will not be syntax-highlighted.

Note about SQL blocks. CudaText has lexer preinstalled, it's lite lexer "SQL ^", and it cannot be used here, because lite lexer cannot be called from normal lexer. But you can install (from "Plugins / Addons Manager") normal lexers: SQL; SQL White; SQL Blue; T-SQL (T-SQL has it's own alias "tsql"). Just install one of them, and it will be used for SQL blocks.


  • Markdown standard tells that the beginning backticks must match the ending backticks, it must be the same amount of backticks. (And the same is valid for tildes.) This is currently not supported in CudaText version 1.151.
  • Python Markdown description tells that the lexer alias may be replaced with the curly-brackets construct like "{ .lang }" or "{ .lang .foo .bar }" or even "{ #someid .lang .foo .bar }". This is currently not supported in CudaText version 1.151.
  • The similar feature of the reStructuredText, as documented here, is not supported.


Folding is the feature allowing to collapse multi-line regions of code. Collapsed region shows the rectangle-like figure on the first line, and other block lines become hidden. Collapsed region can start from any column, but it consumes entire next lines. App shows special column in the "gutter" (vertical band with line numbers), with plus/minus icons - these icons collapse/uncollapse regions. Folding "rules" are configured in the lexer file.

To select an entire folded block, place the caret right before the beginning of the block, and press Shift+Down. Ie, make selection to beginning of the next unfolded line.

There are several options to customize related functionality: call menu item "Plugins / Options Editor Lite" and enter the filter string "fold".

Folded blocks can be rendered in few different ways, this is optional:

  • rectangle-mark at the beginning of the range (maybe after some text in the line)
  • rectangle-mark after the end of the first line of the range
  • "− − −" dash line below the first line of the range

Automatic folding of comments

There is an option "auto_fold_comments" (default is 0 - it's turned off) which allows to automatically create folding ranges from N (or more) consecutive lines, which are all "syntax comments". This works for both line-comments and stream-comments, they can be even mixed (one comment after another, with any amount of blank lines in between, but not for several stream-comments on a single line).


Previously, CudaText allowed something like this, via lexer configuration: all needed lexers must have special settings inside them, and this worked for 2+ lines, not for custom value. After the option "auto_fold_comments" appeared, all 3rd-party lexers should be stripped of those old settings.

Location of folders 'settings', 'py', 'data'

CudaText distributions are portable, if the executable file is located near the "data" sub-folder. So the distribution for Windows is portable (executable "cudatext.exe" is located near "data"), and distibutions from .xz archives are portable too.

Not portable CudaText:

  • Linux: .deb package, which installs binary file to "usr/bin/cudatext" and several data folders to "/usr/share/cudatext".
  • macOS: package, which installs to the "Applications" system folder.
  • Haiku.

For not portable usage, folder "settings" is created here:

  • Linux, *BSD, Solaris: ~/.config/cudatext, or $XDG_CONFIG_HOME/cudatext if this OS variable is set
  • macOS: ~/Library/Application Support/CudaText
  • Haiku: /boot/home/config/settings/cudatext


You can change encoding of document by clicking on statusbar item, or by using menu "File / Encoding". Menu will give list of encodings. Menu gives 2 sub-menus:

  • "Reload as": Reload file in given encoding from disk.
  • "Convert to": Change encoding in memory only (this doesn't save the file).

Possible encoding names for command-line usage:

  • utf8
  • utf8_bom
  • utf16le
  • utf16le_bom
  • utf16be
  • utf16be_bom
  • utf32le
  • utf32le_bom
  • utf32be
  • utf32be_bom
  • cp1250
  • cp1251
  • cp1252
  • cp1253
  • cp1254
  • cp1255
  • cp1256
  • cp1257
  • cp1258
  • cp437
  • cp850
  • cp852
  • cp866
  • cp874
  • cp932
  • cp936
  • cp949
  • cp950
  • iso-8859-1
  • iso-8859-2
  • iso-8859-3
  • iso-8859-4
  • iso-8859-5
  • iso-8859-7
  • iso-8859-9
  • iso-8859-10
  • iso-8859-13
  • iso-8859-14
  • iso-8859-15
  • iso-8859-16
  • mac

Line ends

All major types of line-ends are supported:

  • CR LF (usual for Windows)
  • LF (usual for Linux and Unix)
  • CR (usual for Mac OS 9, now almost not used)

Mixed line-ends (CR with LF with CR LF) in one document are supported. Because of this feature, CudaText saves binary files to disk without corrupting them. To see mixed line-ends, use application option "unprinted_content", which can show text marks ("lf" etc) at line-ends.


  • To change line-ends for all lines in the current document, click statusbar cell for line-ends, menu will appear. You need to save file then. Changed line-ends can be undone via "Undo". Also 3 commands are available in the Command Palette.
  • To change line-ends for individial lines (in CudaText 1.158.3+), use 3 commands in the Command Palette: "change line ends, for line(s) with caret: CR LF / LF / CR".

Groups of tabs

"Groups" are tab sets, each tab has attached editor control. By default only the first group is shown. Totally 6 groups can be shown at once. Menu item "=" (rightmost item in the top menu) allows to choose grouping mode:

  • one group
  • 2 groups: vertically or horizontally
  • 3 groups: vertically, horizontally or 1+2
  • 4 groups: vertically, horizontally or grid
  • 6 groups: vertically, horizontally or grid

First group cannot be empty, at least one tab exists in it. Other groups can be empty: on closing last tab, if it's active, the first group activates.

  • You can drag-drop tabs from any group to any other visible group (drop only on tabs area).
  • You can move tabs to other groups (by group number or to the next/previous), using commands in tab headers context menu.
  • In grouping modes "2 groups" and "1+2" there's a context menu for splitter, to choose splitting 50/50, 40/60 etc.
  • On changing grouping mode, tabs from disappearing group(s) are moved to still visible group.

"Floating" groups are available, besides "fixed" 6 groups, they are inside separate windows (so can be moved to separate monitor). To place some tab to a floating group (1, 2, 3), call context menu over a tab title, "Move tab to group / Floating n" (n=1, 2, 3).


Command "auto-completion menu" (default hotkey: Ctrl+Space) shows auto-completion listbox. It works in several sutiations differently.


Intelligent completion is supported via plugins. For the 2021 year, such plugins exist:

  • LSP Client - supports Microsoft LSP protocol, for lot of languages. Plugin was tested to work good with servers: Python, C++, C#, CSS/SCSS/LESS, JavaScript/TypeScript, Go, Rust.

And specialized plugins:

  • for JavaScript lexer - "JS Tern"
  • for Python lexer - "Python IntelliSense"
  • for HTML lexer - "HTML Completion", gives additional completion for "id" and "class" names
  • for AutoIt lexer - "AutoIt Helper"
  • for SPIR lexer - "SPIR Helper"

In the case of files without lexer, consider to use plugins "Complete From Text" and "Intext Complete". They suggest completions from all words from the current document (or all opened documents, by option).

Static auto-completion files

Some lexers (e.g. PHP, Pascal, Clojure) provide .acp files, which are fixed set of special words, to show in completion listbox. This is very simple completion, which ignores current context, it only suggests matching strings for the word (or string) under caret. These .acp files are stored in the folder "data/autocomplete".

Special HTML auto-completion

Lexer HTML (and lexers with "HTML" in name, see the option "autocomplete_html_lexers") has its special logic, which is built-in in CudaText. It uses data files in the folder "data/autocompletespec" plus built-in code.

Note: what is "tag", "attribute", "value" below? HTML lines has the form like:

<tag attribute1="value1" attribute2="value2" ...> some text </tag>

Completion listbox shows different information depending on context:

  • Caret is on empty space or after "<". Listbox shows list of tags.
  • Caret is on tag name (opening or closing). Listbox shows list of tags (beginning with typed tag).
  • Caret is after opening tag, before closing bracket, on empty space. Listbox shows list of tag's attributes.
  • Caret is on tag's attribute, before "=". Listbox shows list of attributes (beginning with typed attribute).
  • Caret is after tag's attribute, after "=". Listbox shows list of possible values of attribute, for fixed set of values.
  • Caret is inside attribute's quoted value. Possible cases:
    • Some tag/attribute with fixed set of values. Listbox shows list of possible values (beginning with typed value).
    • Tag A, attribute HREF. Listbox shows list of folders and all files (all files can be hyper-linked).
    • Tag LINK, attribute HREF. Listbox shows list of folders and CSS files.
    • Tag SCRIPT, attribute SRC. Listbox shows list of folders and JS files.
    • Tag IMG/INPUT, attribute SRC. Listbox shows list of folders and picture files.
    • Tag FRAME/IFRAME, attribute SRC. Listbox shows list of folders and HTML/PHP/ASP files.
    • Tag AUDIO, attribute SRC. Listbox shows list of folders and audio files (HTML supports few extensions).
    • Tag VIDEO, attribute SRC. Listbox shows list of folders and video files (HTML supports few extensions).
    • Tag SOURCE, attribute SRC. Listbox shows list of folders and audio+video files (code doesn't detect the outer tag: audio, video etc).
  • Caret is after '&' char with optional word-chars after '&'. Listbox shows HTML entities.


About folders/filenames completion. Listbox items list depends on part of the quoted value before the caret. Folder/file names are taken from the folder/subfolder/up-folder of the current editor's document. Some examples, where caret is shown as "|".

  • Value "|end": All filenames.
  • Value "ab|end": Filenames beginning with "ab".
  • Value "bar/foo/|end": All filenames, from subfolder "bar/foo".
  • Value "../foo/bar/ab|end": Filenames beginning with "ab", from relative folder "../foo/bar".


To use auto-completion of CLASS= and ID= names (ie suggest mentioned names for partially typed names), you need the plugin "HTML Completion".

Special CSS auto-completion

Lexer CSS (see the option "autocomplete_css_lexers") has its special logic, which is built-in CudaText. It uses data files in the folder "data/autocompletespec". Several possible cases are handled:

1) Caret is inside {} brackets:

  • Caret is on CSS property name. Listbox shows list of properties (beginning with the typed value).
  • Caret is after CSS property and ":". If that CSS property has fixed set of values, listbox shows list of those values (beginning with the typed value).
  • Special case is "custom CSS properties", which start with double dashes, like "--my-var1". App supports completion of these names, when caret in inside "var()" function. App searches for all custom properties names mentioned in the current document.

2) Caret is outside of {} brackets:

  • Caret is after tag name with char "@". Listbox shows list of CSS at-rules.
  • Caret is after tag name with char ":". Listbox shows list of CSS pseudo-elements, beginning with ":" and "::".

3) Caret is in URL specifier (which is used to specify relative filename of a picture):


Listbox shows folder/file names, if "path" lefter than the caret contains valid partial path. Slashes must be forward ones. For example, url("./|") shows folders/files from the document's folder. For example, url("subdir/|") shows files/folders from the subfolder "subdir".

File URI auto-completion

File URI is file path in the form like 'file://localhost/dir/filename' or 'file:///dir/filename' (host name 'localhost' is often missed). On Windows URI can look like 'file:///c:/dir/filename'.

CudaText supports auto-completion for file URIs, when caret is on 'dir/filename' part, and file path exists on local user's PC.


Auto-completion behaviour for this case is described in the topic about HTML completion, see "folders/filenames completion".


Code-tree is treeview UI control which shows structure of classes/functions/etc, structure info from lexer (if lexer supports this). To show code-tree, activate side-panel (default hotkey: F12). Many lexers support code-tree: most C-based, HTML, XML, CSS, JS etc. Example of tree for Pascal:

atsynedit tree.png

  • Double-click on a tree node moves caret to its text.
  • Tree is filled after few seconds after file opening (search for options ui_tree* to change this pause).
  • When you move caret, tree shows tree node for caret position, after a pause (search for options ui_tree* to change this).

Tree has the "filter" input field: when not empty, tree shows only items containing the filter string. Button X near the input clears the filter. Last entered filter strings are saved/restored to/from sessions.

Tree has the context menu with items:

  • "Fold all"
  • "Unfold all"
  • "Fold level", 2 to 9
  • "Sorted": to toggle the alphabetical sorted mode of the tree

Tree for CSS lexer has additional feature: in the "Colors" node, it shows colored preview-squares.


Console panel

Panel is called by key Ctrl+tilde (Ctrl+`). It has read-only memo with output and edit field. You can type Python commands in the edit field, they will run and show output in the memo. E.g. enter "print(10+12)" and you'll see output "22". Can enter complex commands: e.g. "for i in range(10): print(i)".


  • If you enter command beginning with "=", then it's the same as you enterted "print()". E.g. command "=10+12" will give "22".
  • If you end command with ";", it won't be added to dropdown history.
  • Double-click on memo lines starting with ">>>" repeats entered command (after ">>>" symbols).

You can enter commands from CudaText API. Example clears all bookmarks and sets bookmark on line 11 (these are several commands, run one by one):

from cudatext import *
ed.bookmark(BOOKMARK_CLEAR_ALL, 0)
ed.bookmark(BOOKMARK_SET, 10)

How to use Console as calculator

Call Console panel with Ctrl+` (Ctrl+tilde). In its input field, enter valid Python expressions with leading "=" char. To use "sin", "cos", "pi" etc, first enter command "from math import *".

Example of 3 entered lines and their log in console:

 >>> from math import *
 >>> =pi
 >>> =100/5+2

Command Palette

Command Palette is a dialog which shows all embedded and external (plugin) commands in a single list. To call it, use hotkey Ctrl+Shift+P (or alias hotkey F1). To configure hotkey for some command in Palette, focus this command in listbox and press F9 - additional dialog will appear. CudaText remembers last chosen listbox item in the history file.

Command Palette (and menu-like dialog in Python API) has the filter field. Filter supports fuzzy search, if the option "ui_listbox_fuzzy" is on. "Fuzzy" means that filter leaves only those listbox items, which contain all filter chars in ascending order. Example of fuzzy matches:

  • "fop" matches "file: open file"
  • "gttb" matches "goto text begin"

If option is off, filter uses normal search. "Normal" means that filter leaves only those listbox items, which contain all words from the filter (in any order).

Screenshot shows two Command Palette calls with some filtering: one when the "fuzzy" is on, and another when it's off.


Filter field can find hotkeys too. Enter only hotkey substring, with first "@" char. E.g. "@ho" finds "Ctrl+Home". This search is not fuzzy.

Command Palette lists all internal CudaText commands, all plugin commands (prefixed with "plugin:"), all lexers (prefixed with "lexer:"), and currently opened files (prefixed with "opened file:"). Filter field allows to type hash symbol "#" followed by a letter, to make filtering by category:

  • #p - plugins
  • #l - lexers
  • #f - opened files
  • #r - recently used files

You can type those "hash tags" at begin or end of the field, even without separating space. E.g. "bar#p" will show only plugin commands containing "bar", "#f.md" will show only Markdown files (with .md extension).

Regular expressions

Lexer parser uses EControl regex engine. You use this regex syntax only in the "Lexer Properties" dialog in SynWrite, not in the CudaText normal usage. EControl regex has custom features:

  • class \A: begin of the document
  • class \Z: end of the document
  • class \l: Unicode word-char except the underscore char
  • class \L: inversion to \l
  • lookahead/lookbehind can find match of variable length
  • modifier (?r): \w catches all Unicode letters too
  • modifier (?g): greedy

CudaText search/replace uses TRegExpr engine (by Sorokin, later improved by Alexey Torgashin).

  • To refer to regex groups in the regular expression itself, in the "Find what" field, use syntax \1 ... \9 (and \0 for entire match).
  • To perform replacements with groups, in the "Replace with" field, use syntax $1 ... $9 (and $0 for entire match).

Change case on replaces

With regex, you can change case of found fragments, use modifiers in replace-with field:

  • \l - First char to lower
  • \L - All chars to lower
  • \u - First char to upper
  • \U - All chars to upper

E.g. if found a word, use replace-with field "\L$0" to change word to lowercase (here $0 is group 0, found text).

Modifiers affect only element after them, element is:

  • one char (not string), so "\Uabc" and "\uabc" give same result "Abc" (only one char changed),
  • or group $0 ... $9, so modifier changes case of this group (not only one char).

Output/Validate panels

These lists allow to highlight (e.g. in blue) lines which match some regex. This regex is set by plugin which uses these panels. E.g. plugin HTML Tidy uses panel Validate and sets regex for Tidy result lines. If a line matches regex and highlighted, dbl-click on line navigates to source file.

These panels have hotkeys:

  • Up/Down/PgUp/PgDown/Home/End: move selection in list
  • Enter: navigate to source file, like dbl-click
  • Ctrl+Del: clear entire list
  • Ctrl+C: copy to clipboard entire list
  • Ctrl+D: copy to clipboard selected line
  • Esc: focus editor

Dialog Find/Replace

Find/Replace dialog has hotkeys, which work only when this dialog is focused. Hotkeys can be customized via options "find_hotkey_nnnn".

  • Alt+Enter: Find first
  • Enter: Find next/ Replace next (depends of focused input)
  • Shift+Enter: Find previous
  • Ctrl+Enter: Add new line in multi-line input (multi-line mode is activated by "+" button)
  • Alt+Z: Replace, and find next
  • Ctrl+Alt+Z: Replace, and don't find next
  • Alt+A: Replace all
  • Alt+O: Count all
  • Alt+E: Select all
  • Alt+K: Mark all
  • Alt+Q: Extract


Toggle-buttons have hotkeys too. Hover mouse over them to see floating tooltips about button functions.

Toggle-buttons, ie options, are:

Toggle-button ".*"
Regular expressions (hotkey Alt+R).
Toggle-button "aA"
Case sensitive search (hotkey Alt+C).
Toggle-button "w"
Search for whole words only, ie both sides of found match must be "word boundaries" (hotkey Alt+W).
Toggle-button "O"
Wrapped search: search from beginning after reaching the end (with forward search), and search from end after reaching the beginning (with backward search) (hotkey Alt+N).
Toggle-button "[..]"
Search in selection only (hotkey Alt+X).
Toggle-button "+"
Toggle multi-line mode for both dialog input fields. To add a newline in multi-line fields, press Ctrl+Enter. (hotkey Alt+M).
Toggle-button "*"
Choose allowed syntax elements: Any / Only comments / Only strings / Only comments+strings / etc. This feature must be supported by lexer (and some lexers are limited, support only "comments" or only "strings" syntax elements). Syntax element is detected from left edge position of a found match.
Toggle-button "Hi"
Find and highlight all matches for the current search options. Matches are highlighted in the current editor, with the rounded borders, using the color of "SeparLine" syntax theme item. This highlight is updated on changing the "find what" text, so it is incremental search. Editor auto-scrolls to the first found match (pretty much like ST3 editor). The limitation of this feature: a highlighted match has the single font color for the entire match, so if a match lays over several syntax tokens (e.g. number, dot, normal word), the entire match will have the single font color anyway. This "Hi" button is disabled, when current document has too many lines, see the option "find_hi_max_lines".

Toggle-buttons for "replace" mode:

Toggle-button "?!"
Show confirmation on each replace (hotkey Alt+Y).
Toggle-button "$0"
"RegEx substitute for 'Replace with'". Activates "substitute" for replace-action. When option is off, the replate-with field is taken literally, without interpreting special constructs. When option is on, the replace-with field is processed for special constructs:
  • $0: Text of the whole found match
  • $1 ... $9: Text of the found RegEx group with the index 1...9
  • \n: NL char
  • \r: CR char
  • \t: TAB char
  • \f: FF char
  • \a: BEL char
  • \e: ESC char
  • \xNN, \x{NNNN}: hex code of char
  • \l: lower case of one char
  • \L: lower case of all text
  • \u: upper case of one char
  • \U: upper case of all text

Action buttons in dialog:

Button "|<"
Starts the search from document beginning, ignoring the caret position.
Button ">"
Finds next match, ie continues search forward.
Button "<"
Finds previous match, ie continues search backward.
Button "..."
Shows menu with additional actions:
"Count all"
Count all matches and show the number in the statusbar.
"Extract RegEx matches"
It's enabled only with RegEx option. Finds all matches, all found matches are put to an internal list, list is sorted, duplicates are discarded, and list is put to a new document. Plugin "Extract Strings" does the same task but using the Python RegEx engine.
"Select all"
Finds all matches in a document and places multi-seletions on them.
"Mark all"
Finds all matches in a document and places #Markers on them.
Button "Replace"
If some fragment was found/selected already, it replaces this fragment (by contents of "Replace with" field). If not, it finds next fragment and selects it. If replacement was performed, it finds/selects the next fragment.
Button "Rep all"
Performs replacement of all matches in the current document.
Button "Rep global"
Performs replacement of all matches in all opened documents in all editor groups. After showing the additional confirmation.

The state of dialog search options is saved to the history file, and is restored after app restart.

Text searcher features

Search engine supports actions with multi-selections. This makes sense mainly for mass-search actions (Find all, Select all, Mark all, Replace all).

Search engine has the feature, which is rarely implemented in text editors. When invoked on text selection(s) with the option "Search in selection only", engine doesn't place caret+selection on found match, instead it places marker (#Markers). The marker is placed with the underline (triangle with a line to the left), which shows the length of the found match. Actions "Find next"/"Find previuos"/"Replace" support "in selection only" too, they move that mentioned marker. Note that this feature checks the presence of a single marker in text, it may not work OK if you have some markers already placed.


Second click on the "Search" sidebar button toggles dialog between Find and Replace modes.

Dialog "Go to"

Dialog allows to enter text in formats:

  • 10 (decimal number): Jump to given line number (to line start)
  • 10:10 (two decimal numbers): Jump to given line and column numbers
  • 10% (decimal with trailing "%"): Jump to percents of total line count
  • d100 (decimal with leading "d"): Jump to absolute decimal offset
  • xFFF (hex number with leading "x"): Jump to absolute hex offset
  • value with trailing "+": Extend selection to this position, ie, enlarge previous selection so it overlaps the new position

Also it is possible to show Go To dialog by clicking the statusbar's first cell.


"Session" is a set of opened documents, with properties of each document. CudaText sessions are stored in JSON files with .json and .cuda-session extensions. Default session file name is "history session.json" in the "settings" folder. CudaText shows name of current session in its window title like "filename.txt {session_name} - CudaText".

Program has options:

  • "ui_reopen_session": Save last session on closing, and restore it on start.
  • "ui_reopen_session_cmdline": Allow to restore last session even if some file/folder was passed in the command line (or from the Windows Shell Extension). Note, this gives weird behaviour: N program instances will reopen the same last session + passed command-line file. So this option is mainly for the single instance mode.
  • "ui_auto_save_session": On program closing, save current session without asking.

If some session is opened, program stores document states, on program closing, to session file. If no session is opened, program stores document states to "history files.json" in the "settings" folder.

Session file contains data:

  • List of named documents (file names), and unnamed documents
  • For each document:
    • kind of document: text in editor, picture file, text in viewer (and viewer mode: text/binary/hex/unicode)
    • read-only state
    • first caret position
    • encoding
    • word-wrap mode
    • lexer
    • bookmarks
    • index of top visible line
    • tab size and "tab as spaces" state
    • minimap and micromap visible state
    • ruler visible state
    • non-printable characters visible state
    • line numbers visible state
    • scale factor
    • list of folded ranges (if lexer supports folding)
    • color of ui-tab (if not default)
    • tab title (if not default)
    • modified state
    • code-tree filter string and history of last filters
    • splitting to 2 editors: on/off, vertical/horizontal, percents of size
  • For each modified document: date of modification, full document text
  • Layout/sizes of side panel and bottom panel
  • Layout/sizes of editor groups
  • Index of active editor group and active tab in each group

Plugin "Session Manager" is present in Addon Manager, it gives commands to control sessions: open session file, save session, show list of recent sessions, etc. Session Manager also supports files from SynWrite, with .synw-session extension.

Char map

Char-map dialog can be called in Edit menu. It has 2 modes:

  • ANSI: Shows ANSI char codes from 0 to 255 (codes 128..255 map to different Unicode codes, this depends on active OS locale).
  • Unicode: Shows almost all Unicode code points, they are divided to groups. Change active group using combobox at the bottom.

Click any cell in the grid to insert this char at caret position. Or select a cell with arrow keys and press Enter.


Tab switcher

CudaText has option "ui_tab_switcher_dialog", which activates modern tab switcher for Ctrl+Tab hotkey. This is dialog which allows to switch tab using visit history. For example: press Ctrl, Tab, Tab, Tab, release Ctrl: this goes 3 steps back in the visit history. Visit history is updated on tabs activation (activated tab moves to the top of history).

Dialog lists documents from all tab-groups, with prefixes: "[3-1] /home/user/filename.cpp" for 1st tab in 3rd group.


Alternative way is plugin CudaExt. Plugin gives the command "Choose tab to switch to". You need to assign hotkey Ctrl+Tab to this command (hotkey will be removed from built-in tab switcher). Plugin's dialog is richer than CudaText's dialog: it allows to switch to Console/Output/Validate panels, it allows to cancel the operation.

  • When plugin's switcher is called with pressed Ctrl-key, it shows the dialog.
  • When plugin's swithcer is called without Ctrl-key pressed, it immediately switches to previous tab.



Minimap is wide vertical bar near editor's right side (it can be shown on the left side too, by the option). To show it:

  • Set the option "minimap_show" (show permamently)
  • Use menu item "View / Toggle minimap" (show temporary, for the current document only)

If you drag mouse over minimap, editor will scroll entirely from top to bottom, even for huge documents (mimics Sublime Text behaviour). Text in minimap is painted by pixels, not by font rendering. Minimap is scaled according to CudaText UI, but can be scaled separately too (option "minimap_scale"). Screenshot shows 2 windows with different minimap scale.



Micromap is thin (about 12 pixels) vertical bar near editor's right side. It is not scrollable, it shows overview of entire document from top to bottom. To show it:

  • set the option "micromap_show" (show permanently)
  • use menu item "View / Toggle micromap" (show temporary, for the current document only)

Micromap has several thin columns (from column 1 to column 3, but this can be changed by plugins) for different categories of marks. It shows:

  • full-width single mark: current visible area of editor.
  • on column 1 (leftmost): #Line_states marks.
  • on column 2:
    • marks from plugins: Spell Checker, Highlight Occurrences, etc;
    • marks for bookmarks, if option "micromap_bookmarks" is set; these marks use UI-theme color "editor, line states, added".
  • on column 3: marks for selections, useful for example when command "Find / Select all" makes many selections.

cudatext-micromap .png

Plugins can place marks on micromap, e.g. plugin "Highlight Occurrences" places marks for highlighted fragments, plugin "Spell Checker" places marks for misspelled words.

In the CudaText version 1.144 or newer, micromap can be rendered directly on the vertical scrollbar. To use that, you need 2 options:

  • "scrollbar_themed": true
  • "micromap_on_scrollbar": true


Paste with middle-button-click

To paste like in Linux, with middle-click, you need:

  • set option "mouse_middle_click" to value 2 (in the user.json, of course)
  • install plugin "Auto-Copy to Clipboard"

Plugin "Auto-Copy to Clipboard" activates auto-copying of selection to clipboard, to mimic usual Linux behaviour.

Note: all this works only in the "editor in file-tabs", and doesn't work in Console read-only editor, nor in single-line inputs.


There are two menu items in the View menu:

  • Toggle Full-screen. This maximizes app window (in a special way, OS-dependent, even OS taskbar hides), and also, optionally, turns off some UI elements: toolbar, statusbar, sidebar, side panels (Tree, Project, FTP), bottom panels (Console) etc. Option "ui_fullscreen" has set of chars, each char for one UI element to hide. E.g. option value "tp" hides 2 UI elements ("t" for toolbar, "p" for side panels).
  • Toggle Distraction-free. Like full-screen, but also all UI elements hide (gutter, statusbar, toolbar, sidebar, side panels). No option currently to configure which elements hide.


  • In the Distraction-free mode, app uses option "centering_for_distraction_free" to center the text visually. If you want this centering w/o Distraction-free mode, use the option "centering_width".
  • On macOS full-screen modes hide the top menu bar. To show it w/o returning back, just move the mouse cursor to the top of the screen and hold there for few seconds.

Python integration

Python on Windows

On Windows, Python engine (currently 3.6) is preinstalled. CudaText finds files "python3*.dll" in its folder, and uses file with the latest version number. No options are used to configure this.

You can use not only version 3.6. From CudaText's Addon Manager, install appropriate package, e.g. "Windows_Python37_64bit", and restart the program.

Python engine requires Visual C++ Redistributable for Visual Studio 2015 (32-bit or 64-bit, same as CudaText). Download it from Microsoft site.

So, files needed for Python 3.6 are:

  • "python36.zip"
  • "python36.dll"
  • "python36dlls" - folder with about 18 *.pyd files
  • "vcruntime140.dll" - Microsoft runtime

And file "python3.dll" without exact version (e.g. "36") - this file is not preinstalled, but sometimes it's needed for Python plugins to work property. For example, file is needed for plugin FTP with SFTP support (plugin crashes and shows errors in the Console if "python3.dll" is absent). You can take this file from the Addons Manager - almost each package "Windows_Python3x_xxxx" contains it.

Note for Windows 7. You also need the Update for Universal C Runtime in Windows (KB2999226). Download it from the Microsoft site.

Python on Windows XP

You need CudaText 1.122.0 or newer, and you must install (from Addons Manager) the package named "Windows Python34 32bit". Menu item "Plugins / Addons Manager / Install" must list this package.

No options are needed to configure this older Python, but you need to delete all newer Pythons from CudaText folder:

  • python*.dll: must be deleted
  • python*.zip: can be left as is
  • files *.pyd: can be left as is

Python on Linux, BSD, Solaris

Linux/*BSD/Solaris version uses Python library from OS. Install Python 3.x (usually already installed). Instruction, if Python library was not automatically used:

  • Open file manager, go to /usr
  • Search for "libpython3.*so*"

Or use the terminal command:

$ find /usr -name 'libpython3.*so*' 2>/dev/null
  • If not found, install Python 3.x, and search again.
  • Set option "pylib__linux" ("pylib__freebsd", "pylib__solaris") in the "user.json" config, to one of the found filenames. Write option to the "user.json" or course, not "default.json".

Typical value for Ubuntu:

   "pylib__linux" : "/usr/lib/x86_64-linux-gnu/libpython3.8.so.1.0",

Typical value for Solaris 11.4 x86:

   "pylib__solaris" : "/usr/lib/amd64/libpython3.5m.so",

Python on macOS

On macOS you must install Python 3, from official site python.org. Versions 3.6...3.9 are ok. CudaText will detect this Python. CudaText has option "pylib__mac" with such default value (actual version number is auto-detected):

  "pylib__mac": "/Library/Frameworks/Python.framework/Versions/3.5/lib/libpython3.5.dylib",

If you use Homebrew to install Python on MacOS, CudaText cannot detect it, so you need to write to the "user.json" option "pylib__mac" by hands. Example:

  "pylib__mac": "/usr/local/Cellar/python@3.9/3.9.1_3/Frameworks/Python.framework/Versions/3.9/lib/libpython3.9.dylib",

If you use "virtualenv" from Anaconda with isolated Python, CudaText cannot detect it, so you need to write to the "user.json" option "pylib__mac" by hands. Example:

  "pylib__mac": "/miniconda2/envs/py3/lib/libpython3.7m.dylib",

Note: Please remember to change your version in the variable string to match the version you have installed.

Line states

In the gutter bar, you can see colored thin bars next to line numbers: greenish, yellowish. It is line states. They show state of lines:

  • normal: they have no special color on gutter
  • changed: edited since last saving
  • added: newly inserted lines
  • saved: previously changed/added but saved on last saving

cudatext-line-states .png

Line states help to see which lines were edited since the last opening of a file / last saving of a file. CudaExt plugin gives few commands for line states:

  • "Jump: to next/previous changed lines"
  • "Jump: to next/previous working lines"
  • "Jump: to next/previous saved lines"

How to change icons

Screenshot shows 3 icon sets at once:

  • on the main toolbar
  • on the sidebar
  • on the Project Manager toolbar

cudatext all icons.png

Icons in the main toolbar
To change them:
  • (Optional) Install add-on(s) of kind "toolbar theme" (each add-on gives additional icon set or several sets).
  • Change option "ui_toolbar_theme" in user.json. Option value is some subfolder in data/toolbaricons.
  • Restart CudaText.

Note that plugin "Options Editor" makes it easy - for options "ui_toolbar_theme"/"ui_sidebar_theme"/"ui_tree_theme" it shows the combobox dropdown, which is easy to change.

Icons in the sidebar (vertical band on the left)
To change them:
  • (Optional) Install add-on(s) of kind "sidebar theme".
  • Change option "ui_sidebar_theme" in user.json. Option value is some subfolder in data/sideicons.
  • Restart CudaText.
Icons in the Code-Tree panel
To change them:
  • Install add-on(s) of kind "codetreeicons" (each add-on gives additional icon set).
  • Change option "ui_tree_theme" in user.json. Option value is some subfolder in data/codetreeicons.
  • Restart CudaText.
Icons in the Project Manager toolbar
To change them:
  • (Optional) Install add-on(s) of kind "proj toolbar theme".
  • Change option in the dialog: "Options / Settings-plugins / Project Manager / Config".
  • Restart CudaText.
Icons in the Project Manager file list, and on UI-tab headers
(icons are shown on UI-tab headers by "Tab Icons" plugin). To change them:
  • Install add-on(s) of kind "file type icons".
  • Change option in the dialog: "Options / Settings-plugins / Project Manager / Config".
  • Restart CudaText.


CudaText has toolbar on the top, which can be shown by menu item "View / Toggle toolbar".


To customize it, install plugin "Config Toolbar" from Addon Manager. Plugin gives command (menu "Plugins / Config Toolbar / Customize buttons") to customize toolbar contents: simple buttons, buttons with dropdown menus, separators, icons for buttons.

Plugin also gives command "Hide standard buttons" which allows to hide default CudaText buttons from toolbar. This command shows input box for space-separated indexes of buttons. What are these indexes? Indexes are 0-based numbers of all toolbar items: first button (New File) is index 0, next item (dropdown near New File) is index 1, next item (Open File) is index 2, etc (all separators also have index). So for example, to hide 3rd + 10th items, enter "2 9" into that input box.

Configurable statusbar

Statusbar is fully configurable: you can change order/visibility of cells, width and alignment of cells. Option "ui_statusbar_panels" configures set of cells. Predefined cells are:

  • Caret(s) info. Click on it shows Go To dialog.
  • Encoding name. Click on it shows menu to change encoding of document.
  • Line ends characters. Click on it shows menu to change line-ends in entire document.
  • Lexer name. Click on it shows lexers menu.
  • Tab-char size. Click on it shows menu to change current document tab-size, change "tab as spaces", etc.
  • Text insert/overwrite mode (toggled by Ins key)
  • Mouse selection mode: "-" for normal mode, "||" for column mode (mouse dragging makes column selection even without Alt+ key)
  • Word-wrap mode: off, wrap at window edge, wrap at fixed margin
  • Message from program or plugins (usually it's last auto-sized cell)
  • Font zoom value (in %)

The cell "carets info" shows value of one of options:

  • "ui_statusbar_no_sel": Used when there is no selection
  • "ui_statusbar_small_sel": Used when there is single-line selection
  • "ui_statusbar_str_sel": Used when selection is multi-line
  • "ui_statusbar_col_sel": Used for column-selection mode
  • "ui_statusbar_carets": Used when 2 or more carets are placed

In the above "ui_statusbar_" options, macros are supported:

  • {y}: line index of first caret
  • {y2}: line index of last caret
  • {yb}: line index of first selection beginning
  • {ye}: line index of first selection ending
  • {x}: column index of first caret, tab-chars counted as 1
  • {xx}: column index of last caret, tab-chars expanded
  • {count}: total number of lines
  • {carets}: total number of carets
  • {sel}: number of lines affected by selection(s)
  • {selchars}: number of selected characters, for all kinds of selections
  • {cols}: number of columns in column selection
  • {char}: character at first caret (empty if no char)
  • {char_dec}: character at first caret - decimal code (empty if no char)
  • {char_hex}: character at first caret - 2...4-digit hex code (empty if no char)
  • {char_hex4}: character at first caret - 4-digit hex code (empty if no char)
  • {_ln}: localized string "Ln"
  • {_col}: localized string "Col"
  • {_sel}: localized string "sel"
  • {_linesel}: localized string "lines sel"
  • {_carets}: localized string "carets"

An option exists to change the delay of messages in the statusbar.

This is not used in the main statusbar, but plugin API allows to colorize statusbar cells (used by Vim Mode plugin), and to show icons there.

File viewer

CudaText has internal file viewer, for files on unlimited size. Only visible portion of file is loaded into memory, so viewer is fast for all files. Viewer has several modes:

  • Text: 1-byte encoding, variable line length
  • Binary: 1-byte encoding, fixed width (line breaks are ignored)
  • Hex: 1-byte encoding, fixed width
  • Unicode: like Text, but in UTF-16 encoding
  • Unicode/Hex: like Hex, but in UTF-16 encoding

Combined screenshot shows the different modes in action: Text, Binary, Hex, Unicode.


CudaText suggests to use viewer for files of too big size (bigger than option "ui_max_size_open"). And for files with binary contents.


Viewer has only limited search support, ie not all Find-dialog options are enabled, when file viewer is active. Viewer allows to use "Go to" dialog. In the "Go to" dialog, you can enter "2000" to jump to hex offset 0x2000 (in hex mode, rounded to 16 bytes). If you enter "50%", viewer will jump to the middle. Viewer supports selection of block by mouse, and hotkeys Ctrl+A (Select all), Ctrl+C (Copy to clipboard). Viewer supports double-click to select whole word.

In viewer mode, you can click statusbar fields:

  • Encoding field. You can change viewer encoding only in non-Unicode modes.
  • Mode field, to change view mode: Text, Binary, Hex, Unciode, Unicode/Hex.

Picture file viewer

CudaText has the emdedded picture file viewer. It's activated when you open a file with the picture file type, see the option "picture_types": BMP, PNG, JPEG, GIF, ICO (Windows icon), WEBP (general picture format), PSD (Photoshop image), TGA (Targa), CUR (Windows cursor).

Viewer supports zooming of an image:

  • use Ctrl + mouse wheel
  • click the statusbar cell with the zoom value, and choose one of predefined zoom values: 33%, 50%, 100%, 150%, 200%, 500%, 1000%, 1500%.

While picture is zoomed so that it's bigger than the current window, you can drag the picture by mouse.

While picture viewer is active, Find/Replace-dialog is disabled.

Pair brackets

CudaText has built-in pair bracket finder. Bracket finder can highlight pair brackets, when there is only single caret, and no selection is placed. It finds symbols "()[]{}<>" (configurable per lexer via lexer-specific configs). Bracket finder respects lexer context: it skips symbols inside syntax "comments" and syntax "strings". If caret is placed not directly on/after a bracket, program will find nearest surrounding brackets.

(Long time ago, plugin "Bracket Helper" was needed for this feature, later it was removed from add-ons.)

There are several options:

  • "bracket_highlight"
  • "bracket_symbols" (includes only symbols ()[]{} by default, but you can enable symbols <> for example in HTML lexer specific config)
  • "bracket_distance"
  • "auto_close_brackets"

There are several commands in the Command Palette:

  • brackets: pair highlight: on
  • brackets: pair highlight: off
  • brackets: pair highlight: toggle
  • brackets: jump to pair
  • brackets: select to pair
  • brackets: select to pair, inside (it makes selection smaller by 2 characters)

Brackets auto-pairing logic

Auto-pairing of brackets is controlled by the option "auto_close_brackets". Option supports auto-pairing of brackets and some other chars (quotes, tilde etc).

For single caret

  • If selection is present, and opening bracket is typed, CudaText encloses the selection into 2 paired chars, like "(selection)".
  • If there is no selection, and char is typed (not only bracket-char, but any char from the option), CudaText inserts 2 paired chars like "()", moving the caret inside that pair. Incorrect contexts for the pairing are:
    • Context "\|" - char is typed after backslash-char.
    • Context "|w" - char is typed just before a word-char.
    • Context "w|" - quote-char (single quote, double quote, backtick) is typed after a word-char.
  • If there is no selection, and closing bracket is typed, CudaText may ignore this char or not, it depends on context:
    • Context "f(|)" - app ignores closing bracket and only moves caret righter.
    • Context "f(text|)" - new closing bracket is added.

For multi-carets

CudaText first looks at contexts of all carets. If at least one caret has "not suitable" context, app does not do the pairing, for all carets. So pairing is performed for all or nothing.

For caret with selection, context is considered as OK. And typed char will enclose the selection for that caret.

Word jump commands

CudaText provides several word-jump commands, see them in the Command Palette by entering "go to word":

  • go to word next
  • go to word next + select
  • go to word next, simple
  • go to word next, simple + select
  • go to word previous
  • go to word previous + select
  • go to word previous, simple
  • go to word previous, simple + select
  • go to word end
  • go to word end + select

"Go to word next" vs "Go to word end"?

  • "...next" - jumps to the next word start (left word boundary).
  • "...end" - jumps to the end of the current word (right word boundary), and after that it jumps to the next word end too.

For example, Windows 7 Notepad performs "...next" on pressing Ctrl+Right, while Sublime Text 3 performs "...end" on pressing Ctrl+Right. To configure Ctrl+Right (and Shift+Ctrl+Right) behaviour, re-assign this hotkey from one command to another - to reassign it, press F9 in the Command Palette dialog.

"Go to word next" vs "Go to word next, simple"?

  • "..., simple" command performs simplified jump, it treats all alpha-numerical characters and symbols (#$%^&@ etc) as one group, so it makes single jump over "test@#some!" string.
  • "Go to word next" treats alpha-numericals and symbols as different char groups, and stops at the beginning of each group.

Plugin CudaExt provides such related commands:

  • Cuda-Ext: Jump: Left into CamelCase/snake_case
  • Cuda-Ext: Jump: Right into CamelCase/snake_case

Sorting and finding duplicate lines

CudaText has two sorting methods.

Method 1: Python plugin "Sort", which supports Undo for its commands. It works not fast and takes lot of memory on sorting. It cannot sort huge files, because it reads all file contents from Pascal buffer to Python buffers.

Commands in menu "Plugins / Sort":

  • Sort ascending
  • Sort descending
  • Sort ascending, ignore case
  • Sort descending, ignore case
  • Sort dialog... (shows all sorting options in dialog)
  • Reverse lines
  • Shuffle lines
  • Remove duplicate lines
  • Remove duplicate lines, but keep blanks
  • Remove duplicate lines + origins
  • Remove adjacent duplicate lines (ie nearest repeated lines)
  • Extract duplicate lines (put duplicate lines to a new document)
  • Extract duplicate lines, ignore case
  • Extract unique lines
  • Remove blank lines
  • Remove adjacent blank lines
  • Ini file: sort sections and keys
  • Ini file: sort sections, but not keys
  • Sort e-mail list by domain (lines should be valid email addresses to sort them by domain)

The advantage of "Sort" plugin is that is has additional commands (for duplicate lines, for ini files, for e-mails).

Plugin has config file, you can edit it via menu item "Options / Settings-plugins / Sort". In section [sort] you can change option "allow_all" to 0 or 1 to disable/enable sorting of entire document, if nothing is selected. If selection exists (single selection), plugin handles selected lines.

Method 2: Pascal-based sorting commands, which are named like "(without undo) Sort...". They clear current Undo (ie user cannot undo sorting operation), but they are optimized for speed and memory. Commands don't read document contents into additional buffers, they sort document in-place (changing pointers only). So they work with all files which CudaText can load.

Commands in Command Palette:

  • (without undo) sort ascending
  • (without undo) sort ascending, ignore case
  • (without undo) sort descending
  • (without undo) sort descending, ignore case
  • (without undo) delete all blank lines
  • (without undo) delete adjacent blank lines
  • (without undo) delete all duplicate lines
  • (without undo) delete adjacent duplicate lines
  • (without undo) reverse lines
  • (without undo) shuffle lines


"Markers" are text positions which are shown with red (color in default theme) triangles below them. CudaText gives such commands in the Command Palette:

  • "markers: drop marker at caret": Adds a marker on current caret position.
  • "markers: go to last marker (don't delete)": Moves caret to the last placed marker without deleting it.
  • "markers: collect last marker (delete)": Moves caret to the last placed marker and deletes it.
  • "markers: remove all": Removes all markers in the current document.
  • "markers: swap caret and last marker": Moves caret to the last placed marker, deletes this marker, and adds marker on the previous caret position. Command is to jump to the last marker, second command call jumps back, 3rd command call jumps back, etc.
  • "markers: select to last marker": Makes text selection from caret position to the position of last placed marker.
  • "markers: delete to last marker": Deletes text from caret position to the position of last placed marker.

Markers are utilized by the Snippets plugin.


Snippets plugin finds tab-stops in the inserting snippet text, and places markers for them. After markers are placed by Snippets plugin, Tab-key works in special way - it runs command "collect last marker", ie it jumps to the next marker ("next" by the order of tab-stop: 1, 2, 3... tab-stop 0 is the last). When user collects all markers by Tab-key, this special mode deactivates and Tab-key works as usual again. Command "markers: remove all" also deactivates that mode.

Note about command "Add next occurrence of selected word". This command finds next occurrence, and adds marker (with underline) for the last added selection. This marker is special: it's intended only for this command, and it's auto-removed on a) "Cancel carets" command, b) any text changing, c) mouse click. The reason for this marker is to support "wrapped" search: command runs "wrapped" search when it reaches the document end.

Dialog "Save tabs"

Dialog "Save tabs?" shows on CudaText closing, if at least one document is modified and not saved to disk. Dialog lists all modified file-tabs (usually one file per one file-tab, but it's allowed to have 2 files in a single file-tab). Checkmarks (all checked by default) are used to check/uncheck file-tabs which will be saved on pressing "Save" button. For untitled documents to be saved, program will show "Save as" prompts. Button "Don't save" closes dialog and program, losing modifications. Button "Cancel" closes the dialog, but not the program.

CudaText has the option "ui_reopen_session". When it is true, dialog "Save tabs?" shows additional button: "Don't save / Keep in session", which doesn't save disk files, but stores modified documents to active "session" file. Program will read it on start.

Also CudaText gives the command "dialog: save tabs" in the Command Palette. It shows the same dialog, the difference is that buttons do not close the program.

Hex display of special chars

Editor shows some characters in a "hex form", like "x2000" for character U+2000. For codes below 0x100, hex form is shorter, like "x01" for character U+0001. If single-byte encoding is used (e.g. cp437), then only the short hex form is used. Hex form is rendered with different font color.


Special characters which are always rendered in the hex form (this is not configurable):

  • U+0000...U+001F, except Tab-char U+0009
  • U+2000...U+200F: white spaces + specials
  • U+2028...U+202F: white spaces + specials
  • U+2066...U+2069
  • U+0085
  • U+061C
  • U+FEFF

Tabs features

Control of UI tabs is named ATTabs, and has many features:

  • Pseudo-tab "+" at the end. Option "ui_tab_show_plus".
  • Scrolling arrows (on the left by default), to scroll tabs when there are lot of them and they don't fit. Thin scrolling indicator auto-appears on the top (default color is red).
  • Drop-down arrow (on the right by default), to show menu of all tabs in the current group.
  • Tabs can be placed on all 4 sides: top, bottom, left, right. Option "ui_tab_position".

cudatext-tabs-left .png

  • Layout of "arrows" is customizable. Option "ui_tab_button_layout". Button "+" is available, to replace "+" pseudo-tab, this button is always visible (pseudo-tab can be scrolled away). Button "x" is available, to close the current tab. Screenshot shows the layout with all possible buttons placed on the left.


  • Tabs can be multi-line. In multi-line mode, tabs-control changes its own height. But this height is limited by 2/3 of the window height. Option "ui_tab_multiline".


  • Tabs can have fixed or variable width. "Variable width" means that tabs are auto-stretched to fit the longer title. Option "ui_tab_variable_width". Minimal/maximal width of fixed tabs is customizable.
  • Tabs can be shaped/bordered, or can be flat. Option "ui_tab_flat". Flat tabs are painted with additional colored underline for the active document.


  • Tabs can be dragged by mouse: inside original group or to another groups (use "=" top menu item). And can be moved to specified group index using tab context menu items "Move tab to group n".
  • Program can be used without tabs at all. Options "ui_tab_show" and "ui_tab_disabled".
  • Tabs can be colored, by calling tab's context menu, and "Set tab color..." menu item. Internally, it calls plugin cuda_palette to choose the color, then color is applied. Plugin dialog has several modes (even simplest mode named "60 colors" is enough). By default, only thin line at the edge of tabs is colored, but you can colorize the entire tab using CudaText option "ui_tab_fullcolor". Coloring is saved to session (tab color is usual property of editor).


  • Tabs can have file-type icons, if plugin "Tab Icons" is installed (icons are preinstalled already, they are used by Project Manager). Plugin also allows to assign icons from additional set of 16x16 PNG files.


  • Tabs can show "path suffix" when there are several tabs for the same base filename. In the example picture, we have opened files "t.txt" from 3 different folders, and tabs show that folders after a bullet-char. Feature can show "path suffix" for up to 4 folder levels.


  • When too many tabs are opened, so that they don't fit by width/height:
    • the left/right "arrow" icons become working, they scroll the tabs-control;
    • the reddish "scroll marker" appears at the edge of the tab-control. Picture shows 2 windows with the scroll marker: one with single-line tabs, another is with multi-line tabs.


  • Tabs can be made "pinned" using tab's context menu item "Pinned". Pinned tab caption renders with a "!" prefix char. Commands "Close all tabs" and "Close other tabs" skip pinned tabs. Closing of a pinned tab shows additional confirmation like "Tab is pinned... Are you sure you want to close it?".

Activating internet links

CudaText allows to activate internet links (URLs) and e-mails (e-mail can be with the 'mailto:' and without it). This feature needs that links are automatically underlined in the editor. After the double-click on an underlined link, editor shows small button over the link (button with caption "Open link" or "Send e-mail"), and clicking on this temporary button activates the link.


This works with the default values of 2 options:

  • "links_regex": it must include RegEx, which detects and underlines links
  • "mouse_click_links": it gives choices:
    • don't activate links by clicks
    • activate by single click
    • activate by double click

HTML color codes underlining

CudaText can colorize HTML color codes, which have these forms:

  • #abc
  • #abc0
  • #aabbcc
  • #aabbcc00
  • rgb(100, 200, 100)
  • rgba(100, 200, 100, 0.5)
  • hsl(0, 100%, 50%)
  • hsla(0, 100%, 50%, 0.5)

Two options configure this feature:

  • "underline_color_files": Specifies which file extensions are supported by the feature.
  • "underline_color_size": Specifies the size of colored block in the editor area. It can be simple underline below the color code, or a background highlighting. Background highlighting can be in 2 variants: for entire text, for the fragment inside brackets.

Screenshot shows all 3 variants in different CudaText windows:


UI scaling

UI can be scaled by these options:

  • "ui_scale" (needs suffix for OS): it scales the sizes of UI controls only.
  • "ui_scale_font" (needs suffix for OS): it scales fonts sizes only (both editor text font and UI font).

Auto-detection of current OS scale is implemented for Windows only. And you can ignore the Windows scale auto-detection, by setting the above options.

Additional options are:

  • "ui_tab_scale": it scales UI-tabs font, independent from other options.
  • "minimap_scale": it scales minimap only, independant from other options.
  • "unprinted_symbols_scale": it scales graphics rendered for non-printable stuff: spaces, tabs, EOL text markers.

If you scale UI, you may want to scale the icons as well. But icons are PNG images and cannot be resized, so the solution here is additional icon sets. In the menu "Plugins / Addons Manager / Install" you will find several categories of icon sets:

  • category "sidebartheme" - configured by option "ui_sidebar_theme"
  • category "toolbartheme" - configured by option "ui_toolbar_theme"
  • category "codetreeicons" - configured by option "ui_tree_theme"
  • category "projtoolbaricons" - configured by dialog of Project Manager
  • category "filetypeicons" - configured by dialog of Project Manager

Themed top menu

Top menu (together with some context menus and menu from the "hamburger" icon) can be themed. Only on Windows. This needs the option "ui_menu_themed":true (it's 'true' by default). When option is on, menu font/background/selection/checkmarks become colored from other CudaText UI theme colors. Also, option "ui_menu_themed_font_size" allows to change the font size.

You can also set colors of menu elements directly; dialog "Options / Settings - theme - ui" provides theme items for this. For example, to set the font-color of the top menu, change the color of element "top menu, font" in the dialog.


By default, elements "top menu, ...." in the dialog have the "none" color (crossed rectangles), it means that custom colors are taken from other UI-theme elements.


CudaText gives 2 options to render vertical lines in specified columns:

  • "margin": Integer value, column of "normal margin" vertical line. This margin is used also by the word-wrapping, then "wrap_mode" option is 2 or 3. It is also used by CudaExt plugin's action(s) ("Re-wrap lines by margin").
  • "margin_string": String of space-separated numbers, it makes vertical lines appear at additional columns.

The plugin "Column Marks" adds more features:

  • Commands to set the "normal margin" and/or "additional margins" via prompt dialog. Plugin can save entered value to the user.json config.
  • Commands to move the caret though all margin columns (normal + additional), to the left/right.


Python API

See Wiki page about Python API.

Major plugins Wiki

See Wiki page about major plugins.

Entire plugins list

See the GitHub repository with the readme and links about almost all published plugins. You can make Pull-Request there, if needed.

Kinds of add-ons

Extensions with Python code. They add events and/or commands. Commands can be called then via "Plugins" top menu, but only if plugin's install.inf file doesn't hide menu items in "Plugins". In any case, all commands can be called via Command Palette dialog.
Syntax highlighting files. For ex, Arduino lexer adds item "Arduino" to the lexer menu. Some addons can add 2 or more lexers, for ex "HTML nnnnnn" addons often add 2 lexers: one is visible in the lexer menu, another one is hidden (it supports embedded blocks).
Sub-plugins for CudaLint plugin. Each supports some lexer (or several similar lexers). To use them, install CudaLint plugin, open your work file, and call CudaLint commands: it calls appropriate linter and shows colored bookmarks on error/warning lines.
Sub-plugins for CudaFormatter plugin. Each supports one or several lexers and can reformat source code for these lexers. Examples: Python ReIndent, JS Sort Imports, AStyle Format.
tree helpers
Plugins which show Code-Tree structure for some lexer (useful if language is complex, and lexer cannot handle all language complexity).
Collections of text fragments, for "Snippets" plugin (which is required to use snippets). See details in the CudaText_plugins#Snippets.
CudaText UI translations. For ex, JP translation changes all menuitems + dialogs to JP language. Dialogs of plugins are not affected.
Translation of plugin strings to different languages. This includes translation of strings from Python code, and strings from "install.inf" files.
UI/syntax themes for the "Options / Color themes" menu. UI themes change colors of CudaText interface. Syntax themes change colors of words in syntax highlighted files.
sidebar themes
Icon sets for the sidebar (vertical row of buttons on the left side).
toolbar themes
Icon sets for the main toolbar (horizontal row of buttons on the top).
toolbar x icons
Icon sets for plugin "Config Toolbar", for user-added buttons.
file type icons
Icon sets for the file list of "Project Manager" plugin. Usually these are repackaged icons for VS Code editor.
proj toolbar icons
Icon sets for the toolbar of "Project Manager" plugin.
code-tree icons
Icon sets for the Code-Tree (icons are visible in the Code-Tree with some lexers, e.g. C#).
build systems
Configuration files for different external tools, for the Runner plugin. Runner plugin supports build-systems for Sublime Text 3 (only JSON configs, without support for additional Python codes).
Packages with possible binary files, which will be unpacked to the CudaText installation folder. For the date 2021.08, these are only Python engines, for CudaText Windows build.

Program performance

Startup time

CudaText starts quite fast: about 0.3 sec with about 30 plugins (all preinstalled + some popular plugins), on Linux, on CPU x64 Intel Core i3 3GHz.

If no additional plugins are installed, or Python engine is disabled (ie not configured on Unix, or Python DLL files are deleted on Windows), then it starts even faster. If configuration/history are clean, it starts faster. If bottom panel is hidden on start, via option "ui_bottom_on_start":2, it starts faster.

Performance of loading huge files

It's interesting how fast Linux editors open huge log files. Test file has about 300M size, 4M ASCII lines, it's created by Python script:

f = open("a.log", "w")
for n in range(4*1000*1000):
    k = 120-n%100
    f.write(str(n+1)+' '+chr(k%26+ord('a'))*k+'\n')

PC is HP Pavilion g6, CPU AMD A10 x64, 4 cores, RAM 8G, Ubuntu 18.04. Each time is average of 2-3 tries in the same session.

  • CudaText 1.98: 9 sec.
  • Sublime Text 3.2: 11.5 sec.
  • Geany 1.32: 6.5 sec., jump to end: additional 4-5 sec.
  • Kate 17.12.3: 7 sec.
  • gedit 3.28.1: 1 min 10 sec.
  • Vim 8.0, NeoVim 0.2.2: 3 sec.
  • Emacs GUI 25.2.2: 2 sec., after showing confirmation for big file
  • Bluefish 2.2.10: 24 sec.

Performance on huge lines

It's interesting how some Linux editors handle huge lines. Tested several editors on Ubuntu 19.10 on Intel i3 CPU. With XML file with a single line of length 4M. XML file contains line like <id name="nnnnnnnnnnnnnnn"> with the huge "name" value of 4M.

Python script to generate test file:

f = open("a.xml", "w")
f.write('<id name="')
for n in range(1, 4096):
    f.write("n" * 1024)
  • CudaText 1.96. Opens file: 1.5sec. Caret moves at the end of line: very fast (<0.1sec). Editing of this line: adding each char is about 0.5sec.
  • Sublime Text 3.2. Opens file: 2sec. Caret moves at the end of line: each Left/Right arrow is 0.5sec delay. Editing of this line: not fast.
  • Geany 1.35. Opens file: about 10sec, then for next 5-10sec I cannot place caret by mouse, then it works. Caret moves at line begin: fast, caret moves at line end: slow (delay 0.5sec after each Left/Right key). Editing at the end: adding each char is about 6sec.
  • Kate 19.04. Gives colored panel "The file ... was opened and contained lines longer than ... The lines were wrapped and document is set to read-only mode...". Caret moves at the end of wrapped doc: fast. Editing is disabled.
  • gedit 3.34. Hanged on opening file (from command line and from editor), waited it for 20sec.
  • Vim 8.0. Opens file: 2-3sec. In word-wrapped mode. Caret moves at the end of line: each Left/Right command (Vim hotkeys) is 2sec delay. Editing of this line: adding each char is about 3sec.
  • Emacs 26.3 GUI. Opens file: 1sec. In word-wrapped mode. With the statusbar error "Internal error in rng-validate-mode triggered at buffer position 10. Stack overflow in regexp matcher". Pressing Ctrl+End to move to end: editor hanged with "wait" cursor.
  • Bluefish 2.2.10. On opening file, gives the warning about too long lines, on choosing "don't split lines" it hanged, waited for 30sec.

Performance of built-in sorting

Test on ~100M text file with short ASCII lines. Test on Ubuntu 19.10 on Intel i3 CPU.

CudaText 1.97:

  • sort time: 18sec
  • sort time with ignoring case: 19sec
  • memory used after file loading: ~1.0G
  • peak memory used on sorting: the same (inplace sorting in the same list)

Sublime Text 3.2:

  • sort time: 14sec
  • sort time with ignoring case: 16sec
  • memory used after file loading: ~1.3G
  • peak memory used on sorting: ~3.3G

Color themes

Color themes introduction

There are two kinds of themes:

  • UI themes, file extension .cuda-theme-ui
  • Syntax themes, file extension .cuda-theme-syntax

Two dialogs allow to paint these kinds of themes. To paint a theme:

  • Call dialog: "Options / Settings - more / Settings - theme - nnnnn"
  • For UI themes: customize colors in dialog
  • For syntax themes: customize lexer-styles in dialog
  • For syntax themes: test theme at least on JavaScript/HTML/CSS/C/Pascal/Ini/Markdown lexers. On what files to test:
  • New theme files are saved in the subfolder "data/themes"

Don't configure custom lexer styles in the Lexer Properties dialog, if option "ui_lexer_themes" is on (usually it's on), because syntax-theme will override all your colors from that dialog. You can configure colors there, if option is off.

UI theme empty values

The following UI theme items allow "none" values, it means that JSON theme-file stores the empty value for them, and plugin API returns COLOR_NONE value for them.

  • EdBlockStapleActive: when "none", it falls back to EdBlockStaple
  • TabFontActive: when "none", it falls back to TabFont
  • TabCloseBg: when "none", tab 'x' background is not painted
  • StatusFont: when "none", it falls back to ButtonFont
  • StatusBg: when "none", it falls back to TabBg

Plus the following items, which colorize the main menu on Windows:

  • MenuFont: when "none", it falls back to TabFont
  • MenuFontHotkey: when "none", it falls back to MenuFont, then to TabFontMod
  • MenuFontDisabled: when "none", it falls back to TabBorderPassive
  • MenuBg: when "none", it falls back to TabBg
  • MenuSelBg: when "none", it falls back to TabOver

How to create theme package

  • If your theme files need some sort of 'suffix' (e.g. "dark", "light", "alternative"), put these suffixes into round brackets, after space-char, in the filename. For example, name the file "brackets (dark).cuda-theme-ui" instead of "brackets-dark.cuda-theme-ui". This is required by Addons Manager plugin, which will need to find the add-on package for your theme.
  • Create such file "install.inf" in UTF-8 encoding (without BOM):
title=MyName UI theme (by AuthorName)
  • Make zip file "theme.MyName.zip" with files "MyTheme.cuda-theme-nnnnn" and "install.inf".
  • Test zip file: open zip file in CudaText, confirm installation.
  • Publish file at forum or https://github.com/Alexey-T/CudaText/issues

How to see all UI theme items

  • "editor, font" - color of font when no lexer is active. Click statusbar field with lexer-name, call "none".
  • "editor, disabled state, font/bg" - editor shown with this bg-color when Replace dialog runs action, with option "confirm on replace" (during confirm message editor is disabled), if no lexer active
  • "statusbar alt" - shown on 2nd statusbar, run in console:
    msg_status_alt('dd', 8)
  • "search progressbar" - to see it, call Replace dlg, with regex, with confirmation (2 options in Replace dlg), replace "." (any char) to "www"
  • "editor, marked range bg" - shows for marked-range, to set marked range from line 5 to 10 use console:
    ed.set_prop(PROP_MARKED_RANGE, '5,10')
  • "editor, markers" - to see markers, call Commands dlg (F1), command "drop marker at caret".
  • "editor, separator lines" - lines show eg for lexer Pascal, above "function"/"procedure".
  • "listbox, ..." - call Commands dlg (F1 key)
  • "listbox, ..., auto-complete..." - call C or Pascal lexer, then press Ctrl+Space to call auto-completion (listbox has 3 columns, 3rd shows not for all items)
  • "splitters, main" - shown near Sidebar (vertical) and above Bottom panel (horizontal)
  • "splitters, groups" - shown between groups (vert/horz), activate 2-3 groups using "View" menu

Meaning of syntax-theme elements

  • Id: Normal id (identifier) or text.
  • Id1: Special id, used e.g. for class names (when it is mixed-case id) or const names (when it is upper-case id).
  • Id2: Special id, used e.g. for syntax constants (true, false, null...) and standard functions (sin, abs, max...).
  • Id3: Special id, used e.g. for measurement units (mm, Kb, px...) and preprocessor directives.
  • Id4: Special id, rarely used, e.g. Python uses it for function names after "def".
  • IdKeyword: Special id, used for syntax keywords.
  • IdVar: Variables, e.g. $name in PHP and Bash.
  • IdBad: Incorrect/misslepped id.
  • String: String literals.
  • String2: String literals, used e.g. for RegEx constants.
  • String3: String literals, one more kind, rarely used.
  • Symbol: Non-word symbols, ie brackets/punctuation/etc.
  • Symbol2: Non-word symbols, used when syntax needs another style for e.g. assignment/math operators.
  • SymbolBad: Incorrect non-word symbols.
  • Comment: Comments.
  • Comment2: Comments, used when syntax needs another style of comments, e.g. shebang in Bash.
  • CommentDoc: Documentation comments, ie comments which are parsed by special tools.
  • Number: Numbers (decimal, hex, octal, floating...).
  • Label: GoTo operator labels, or another special id.
  • Color: Color constants, like #RRGGBB in HTML/CSS.
  • IncludeBG#, SectionBG#: Styles which have background color set, and foreground color unset (none). Used to highlight function blocks, sub-lexer blocks, parts of a file, etc.
  • BracketBG: Style with background+foreground colors. Used to highlight paired brackets, begin/end keywords, repeat/until keywords (when "dynamic highlighting" option is on) etc.
  • CurBlockBG: Style with background color set, foreground color unset. Used to highlight block under caret, when "dynamic highlighting" option is on.
  • SeparLine: Frame color for Find/Replace dialog's "Highlight all" ("Hi") results.
  • TagBound: HTML tags: angled brackets.
  • TagId: HTML tags: tag names.
  • TagIdBad: HTML tags: incorrect tag names.
  • TagProp: HTML tags: properties/attributes of tags, before "=" char.
  • TagPropBad: HTML tags: incorrect props/attrs of tags.
  • TagInclude: Tags used for inclusion of sub-lexer blocks. Used e.g. in PHP, <? ?>.
  • LightBG#: Styles with bright background color, and normal foreground. Used e.g. in Diff to highlight deleted (LightBG1) / changed (LightBG2) / added (LightBG3) text blocks.
  • Pale#: Styles with pale (barely visible) foreground color. Rarely used.
  • TextBold: Style with bold font.
  • TextItalic: Style with italic font.
  • TextBoldItalic: Style with bold+italic font.
  • TextCross: Style with crossed/strikeout font.

Tech topics

Encoding detection

Encoding detection works by this pseudo-code:

  // Corresponding source code is in repository ATSynEdit, file atstrings_load.inc,
  // procedure DoDetectStreamEncoding and
  // procedure TATStrings.DoLoadFromStream

  if file_has_signature(UTF8) then

  if file_has_signature(UTF32_LE) then

  if file_has_signature(UTF32_BE) then

  if file_has_signature(UTF16_LE) then

  if file_has_signature(UTF16_BE) then

  if file_size > 50M then

  if encoding_saved_to_history_file(enc) then
    // it returns the "enc" param

  if option "def_encoding_utf8":true then
    enc = UTF8
    enc = ANSI // "ANSI" codepage is OS dependent
  detect = file_detect_utf8_content
  // it can get 3 values: 
  //     UTF8_Unknown: only ASCII chars present
  //     UTF8_ok: correct UTF8, non-ASCII, chars present
  //     UTF8_broken: broken UTF8 chars present
  if detect == UTF8_ok then
  if detect == UTF8_broken then
    enc = ANSI

  if file_detect_by_python_standard(detect) then
  // it returns detected encoding in "detect" param

  if file_detect_by_xml_signature(detect) then
  // it returns detected encoding in "detect" param

  if file_detect_utf16_content(detect) then
  // it returns detected encoding in "detect" param

UTF-8 content detection works by first 8K of file. UTF-16 content detection works by first 5K of file. If encoding was detected as UTF8, the file loader checks the content again (the entire file size now) for UTF8 chars correctness, and if it finds "not correct UTF8 chars", encoding will be changed to ANSI.

ANSI maps to one of real codepages, it depends on current Windows locale. On non-Windows OS, ANSI maps to cp1252.

What is "file_detect_by_python_standard"? It is detection by this standard. Encoding name is searched by RegEx in the first 1-2 lines of file, if they are comment lines. Comments of these kinds are supported: // # ; --. For simplicity, comment chars are skipped, ignoring current lexer, so it works for all files and all lexers.

What is "file_detect_by_xml_signature"? It is detection by signature, in the first file line, like this:

<?xml version="1.0" encoding="ISO-8859-9"?>

Reduced functionality for big files

CudaText has the following optimizations for big files and huge lines:

  • CudaText refuses to load files >500Mb. See the option "ui_max_size_open":500 (in Mbytes). Program allows to open such files in built-in viewer (without editing).
  • Word-wrap mode is automatically turned off, when total lines count in document is huge. See the option "wrap_enabled_max_lines":60000. When word-wrap mode is off, editor's work is much faster.
  • Program refuses to activate "normal" lexer for big files >2Mb. See the option "ui_max_size_lexer":2 (in Mbytes). Note that "lite" lexers with suffix "^" are still enabled for big files.
  • If file is loaded in "normal" lexer, but count of lines is big, program disables finding of fold-ranges. Syntax coloring works, but folding doesn't work. See the option "lexer_folding_max_lines":10000.
  • If file is loaded in "normal" lexer, huge lines are ignored by lexer parser. See the option "max_line_len_parsed":4000.
  • If file is loaded in "normal" lexer, dynamic highlightings are disabled in big files. See the option "lexer_dynamic_hilite_max_lines":2000.
  • For any files, when too many multi-carets are placed, program disables/clears the Undo-information for editing. See the option "undo_max_carets":5000.

How to open files in a new tab instead of a new window

Option "ui_one_instance" controls it, so change it to 'true' (without quotes, in "user.json"). This option is here for several years already, but people are asking this question again and again (forum, GitHub, Linux forums). Seems the term "instance" is not known very good, people cannot find this option easily.

How to compile CudaText

Install FPC and Lazarus:

  • download FpcUpDeluxe. On Windows, you must unlock .exe file in the Windows Explorer dialog.
  • in FpcUpDeluxe, choose FPC 3.0.4 or 3.2.0, install it first.
  • in FpcUpDeluxe, choose Lazarus 2.0 or "trunk", install it next.

Modern way for app sources.

There is Linux script CudaText_up - it downloads sources to ~/cudatext_up, then calls Lazarus to compile them. You can use it with FPC cross-compilers, installed from FpcUpDeluxe, script will compile CudaText for any of available platforms. Without cross-compilers, script makes CudaText only for the current platform. It puts result to ~/cudatext_up/bin.

Old way for app sources.

  • install .lpk packages into Lazarus (find all .lpk files, open them in IDE, install from Packages dialog)
  • in the Lazarus component palette, you should see:
    • "AT Controls" tab: TATButton, TATButtonsToolbar, TATListbox, TATScroll, TATSynEdit, TATLabelLink, TATGauge
    • "Python" tab: several items
  • in Lazarus, open "cudatext.lpi" project, compile it

How to install plugins from GitHub

First, you need to know GitHub repository (repo) URL of plugin. For example, https://github.com/kvichans/cuda_find_in_files . If you have plugin already, then you can see this URL in the plugin's install.inf (line "homepage=").

Next, call CudaText menu item "Plugins / Addons Manager / Install from GitHub". Enter URL in the suggested dialog. Addons Manager will install latest version from GitHub. Addons Manager supports all branch names ("master", "main" and others), it will show menu of branch names if there are several branches in the repo. The repo must have correct file "install.inf" in the root, otherwise Addons Manager may not detect the plugin in the repo.

After you entered the URL, Addons Manager shows messagebox:

GitHub repository can be cloned (using "git clone") or can be downloaded as zip file.  If you clone, Addon Manager's Update dialog will update add-on using "git pull", which is recommended.
Buttons: Cancel / Download as zip / Clone repo.

Better to choose "Clone repo" here, this will allow to update plugin directly from GitHub. Choosing the "Download as zip" is ok, but you cannot update plugin from GitHub, you can update plugin only from the released versions from SF.net.

How to simply install many add-ons

  • In the dialog "File / Open file", you can multi-select files in list - with Ctrl+click (on Windows) or Shift+arrows.
  • Use command "Plugins / Addons Manager / Download all", which saves all addons zip files to some folder. When done, install many addons from this folder using "File / Open file" multi-selection.
  • There is this page with zipped collection of all addons, but it is updated not often.

How to make translation

Translation template file is in the folder "data/lang". The template file cannot be activated from "Options / Translations". How to prepare the translation zip package:

  • make the file "nn_NN.ini" (UTF-8 with BOM)
  • use standard locale names in filename, e.g. ru_RU pt_PT ja_JP (this is needed for plugins which use Python translation API)
  • write your contacts in the first commented lines. Comments must begin with ";" at line start. Also you can add other comments.
  • to set accelerator-chars for menus/dialogs, use "&" char (e.g. "Open &file"). If needed "&" char as is, duplicate it as "&&".
  • note: Linux Ubuntu font is about 1.3 times wider, than on Windows
  • make the file "install.inf" with such text:
title=LangName translation (by AuthorName)
  • make the zip file "translation.nn_NN.zip", it must contain files nn_NN.ini, install.inf
  • test this zip file: open it in CudaText via "File / Open", and check it's installed
  • publish this zip file, at CudaText forum or at GitHub issues https://github.com/Alexey-T/CudaText/issues
  • if package is OK, it will be at SourceForge downloads, and in Addon Manager

How to make translation of Plugins menu

CudaText supports translation of Plugins menu items. For example, you have plugin with module cuda_nnn, which has "install.inf" with such menu items:


Then you need to create files like "ru_RU.ini" in the folder "data/langmenu/cuda_nnn". Create folder "langmenu" inside "data" if it's absent. Files must be in UTF-8 no BOM encoding. They must have section "menu". All items in the ini-file are optional.

MyPlugin=local name
ItemOne=local name of item
ItemTwo=local name of item
SubMenu=local name of menu

To distribute those translation(s), make zip file like "langmenu.MyPlugin.zip", which must have "install.inf" and folder "cuda_nnn" (you can put more folders, for several plugins, if you want so). Install.inf contents:

title=Translation of menu items of MyPlugin

Submit that zip file to CudaText GutHub page, or post it to the forum.

How to copy word under caret to clipboard

A1: Install "Macros" plugin. In its dialog start recording a macro, and call these commands using "Command Palette":

  • command "selection: select words at carets"
  • command "clipboard: copy"
  • command "selection: cancel selection"

Then assign a hotkey to this macro (in the "Command Palette", find your new macro and press F9).

A2: Plugin "CudaExt" has commands:

  • plugin: CudaExt: Copy word or [expression] or 'expression' without selection
  • plugin: CudaExt: Replace word or [expression] or 'expression' with clip

It's good to use these commands with hotkeys Alt+Left and Alt+Right (assign it in the "Command Palette").

Linux: In Qt5 version, text is shifting on selection

Q1: After some typing, the caret get unaligned with the text. It sort of creeps into the text, making it both tricky to read and tricky to edit.

Q2: When I select text that is inside a string literal (for example), the beginning of the selection gets a space before it, shifting the selected text to the right. As I select more the text continues to squish around.

A: That's the issue specific to (Linux) Qt5 version. It's fixable by the option "renderer_tweaks" (for Linux: "renderer_tweaks__linux"). Description of this option in the default config:

Value is a string of several chars:
if 'w' in value: Use simplified calculation of average character width.
                 On Windows, 'w' is good.
                 On macOS, 'w' is bad.
                 On GTK2, 'w' is not needed.
                 On Qt5, 'w' gives various results, it depends on Desktop Environment.

All you need is to remove "w" char from the "renderer_tweaks__linux" value. In the user.json config:

  "renderer_tweaks__linux": "",

On macOS, changing the option "renreder_tweaks__mac" is usually not needed - default value works good. But in Qt5 version, CudaText cannot detect Desktop Environment settings, so default value is wrong sometimes.

Linux: How to reinstall missed files

Sometimes it's needed to reinstall missed files, e.g. when you have deleted some lexers from "Lexer library" dialog. Simple re-run of .deb installer works, but it will not reinstall deleted data-files. Why? App has copy of its data-files in ~/.config/cudatext (see the topic about location of data+settings dirs). Binary (not deb installer!) makes this copy - only when binary version is not equal to the version stored to settings/packages.ini, "app" section. After you delete that "app" section, and run the binary (not deb installer), binary will refresh files from /usr/share/... to ~/.config/cudatext/...

Linux: Difference between gtk2/qt5 versions

Versions for gtk2/qt5/etc are compiled for different widget-sets, all functions are the same.

  • Different widget-sets make different look of native UI controls (e.g. buttons - but only native buttons, note that Find/Replace dialog has not native buttons), native scrollbars, native File-Open/Save dialogs.
  • Different widget-sets need different value of "ui_buffered*" option. So one value of "ui_buffered__linux" is OK for gtk2, while may be worse for qt5.

So far, different widget-sets are supported for Linux only.

Linux: Keyboard input problems

1) Keyboard input is duplicated.

This is known problem, related to some Input Methods (IM) in Linux. To see what is your active IM, open Terminal and enter:


Known IMs with problems: scim, xim. To fix: change IM from e.g. "XIM" to "none" in the Language Support settings, then chars should not duplicate.

2) Keyboard input misses accent chars.

On some systems, national keyboards (e.g. French) may miss entering of accent chars. This can be solved by changing the Input Method (IM) in the system. See here for example.

In short:

  • Install "ibus" package
  • In the OS environment file, set 2 variables (for 2 builds of CudaText, gtk2 and qt5):
    • GTK_IM_MODULE=ibus
    • QT_IM_MODULE=ibus

Unix: Program takes 25 seconds to start

Q: CudaText takes exactly 25 seconds to start-up. (In fact a few ms more than that). I am sure the problem is at my end, but cannot place it. It is waiting for something and is timing out.

A: As expected, nothing to do with CudaText as such. Setting the following environment variable solves the issue:


Unix: Program takes 60 seconds to start

Q: When I open any Lazarus/GTK2 application, I get a blank window that will timeout after 60 sec and the application will appear then. If I kill this blank window, the application lauches directly and the CRITICAL output resulting from my kill is always the same:

   (app_name:1299276): Gtk-CRITICAL **: 19:03:24.607: IA__gtk_widget_hide: assertion 'GTK_IS_WIDGET (widget)' failed
   (app_name:1299276): Gtk-CRITICAL **: 19:03:24.607: IA__gtk_widget_destroy: assertion 'GTK_IS_WIDGET (widget)' failed

If I wait for the timeout there is no output and everything works fine. This issue appeared to me when I tried to use CudaText.

A: Start the application with "-disableaccurateframe" parameter.

Linux: How to use middle-click paste

  • Set option "mouse_mid_click_paste" to true (in user.json).
  • Consider to install plugin "Auto-Copy to Clipboard", which emulates Linux editors behaviour: copying to clipboard by simple text selection (no need to use hotkey Ctrl+C).
    • This plugin has options to copy selection to a) usual clipboard, b) GTK primary selection (CudaText GTK builds only)

Linux: Installation

.deb package. To support .deb package installation, program performs copying of its files, from .deb installation folder to the settings folder. Ie, when binary "cudatext" (it can be in any folder, e.g. in /usr/bin) starts, it checks, if "data/lexlib" exists near the binary, and if not, it copies folders "py", "data", "settings_default" from .deb installation folder to "~/.config/cudatext" (default location of settings, it can be changed by command line option). Program does this not always, it reads the "settings/packages.ini", and checks there [app] "ver" value. If value not equals to the binary's hardcoded version, program does that copying. So copying occurs once, after .deb package was upgraded.

.xz package. It is intended that user just unpacks this archive, to subdirectory of home-directory, and then runs binary "cudatext" from there. This is simpler way. But additional way is also possible - you can "install" the program, so that "cudatext" will be runnable from Terminal. The "installation" is:

  • unpack CudaText .xz archive to some temp folder
  • copy file "cudatext" to /usr/bin
  • copy folders "py", "data", "settings_default" to "~/.config/cudatext"
  • delete mentioned temp folder

When you run "cudatext" (from /usr/bin), settings folder "~/.config/cudatext/settings" will be created automatically.

Note, that you must download proper package for the proper architecture (x64, ARM, AArch64) and proper OS. Sometimes users download Solaris package on Linux, so "cudatext" file cannot be run.

Linux: Arch Linux packages

The GTK2 and Qt5 binaries can also be installed via the AUR if you are on an Arch Linux based system:

Linux: Qt5 build

For CudaText Qt5 version, library libQt5Pas is required, version 1.2.8 or newer.

You need the latest libQt5Pas from these packages.

On Ubuntu:

$ sudo apt install libqt5pas-dev

On Manjaro:

$ pamac install qt5pas

FreeBSD: App cannot run

If you run app in Terminal, you'll see an error about missing .so file. Reason of this error: FreeBSD version was compiled on Linux with different .so files. To fix error, run command in Terminal:

$ sudo ln -s /usr/local/lib/libiconv.so.2 /usr/local/lib/libiconv.so.3

macOS: App cannot run

There is known issue, when macOS AArch64 version (ie ARM 64-bit version) cannot be run. The following command clears the extended attributes from the bundle, and it can be run:

xattr -cr /Applications/CudaText.app/

(Adjust the file path, if you put the application bundle to a different place.)

Also note, that our application bundle is not digitally signed. So to run it (the first time you do it), you should right-click the application bundle, and choose "Open" menu item, and confirm that you trust the vendor.

How to select extra symbols by double-click

Some languages consider special symbols as word-chars. For example, in PHP, "$" symbol is part of a variable name, so double-click should select "$" together with other word-chars. Follow these steps to add extra symbols (e.g. "$") to word-chars.

  • Open new file-tab, activate your lexer (click the lexer-cell in the statusbar)
  • Call menu item "Plugins / Options Editor"
  • In the Options Editor dialog:
    • Select item of option "nonword_chars", read the description about this option in the bottom
    • Your lexer name must be pre-selected in the combobox on the dialog bottom
    • Check the checkmark "For: lexer", so that your option will go to the lexer-specific config
    • Enter new value of the option "nonword_chars" now. Copy/paste the value from the "Default" field, and remove some special symbols from that value.
    • Press Enter-key in the input field. Value must appear in the list of options in the "Lexer" column.
  • Close Options Editor, restart the program

What does this procedure do? It creates (or modifies) file "[CudaText]/settings/lexer LexerName.json" to be like this:

  "nonword_chars": "-+*=/\\()[]{}<>\"'.,:;~?!@#%^&|`"

How to upgrade but keep all the settings

  • Q: CudaText for Windows. How can I upgrade but keep all the settings the way I have configured them - including themes, icon sets, etc (basic settings I could just copy the settings file over - but I'm not sure what to do for the icons and the rest...)
  • A: Copy all files from the zip package, overwriting old files. All user settings are located in "settings" (which is absent in the zip package) and "data" (in different files). If you did not modify CudaText preinstalled files, you will not loose any settings.

How to customize top menu and context menu

See the page CudaText_plugins#Configure_Menu.

How to help the author to reproduce a bug

Bugs are often cannot be reproduced on author's PC because of different "user config", "lexer-specific configs", plugins configs. To help the author, make the ZIP file with CudaText folder, add your test file(s) there too, and send this ZIP to e-mail support(@)uvviewsoft.com .

What CudaText folder to pack?

  • On Windows: the folder where you copied the program. Exclude files EXE DLL PYD ZIP from ZIP.
  • On macOS: ~/Library/Application Support/CudaText.
  • On Linux, other Unixes: ~/.config/cudatext, or $XDG_CONFIG_HOME/cudatext if this OS variable is set.

Make the bug reproducible on your CudaText folder on your test file(s). Put your test file(s) in ZIP too. If needed to reproduce the bug, create the session using Session Manager plugin (bug may be visible only with some session). Put session file in ZIP too (usually it's already in the "settings" subfolder).

Behaviour of column selection

CudaText gives two modes of column selection, which have differences when you select over wrapped lines, or lines with full-width characters. This is controlled by the option "carets_primitive_column_sel".

  • Value "true": "pritimive mode" which behaves much like Sublime Text. In this mode editor places multi-selections over visual rectangle of characters. In this mode, one line can have 6 chars selected, and another line can have 8 chars selected. This depends on visual positions of chars in those lines.
  • Value "false": in this mode, all affected lines have the same number of selected chars. But when full-width chars (e.g. CJK) are present in text, selection may look weird. Here is an example picture where starting lines are ASCII and ending lines have full-width chars.


It is not a bug. In this example, user selected column block from column 7 (at line 1) until column 20 (at line 6), so column block takes columns 7...20 from all lines. On first ASCII lines, columns 7...20 take different visual area, than columns on last lines. When you copy/paste that block to another program, block may look differently. But that block contains equal number of chars on each line.

Even more weird look happens when user selects column block over word-wrapped lines.


Here is the program's logic in all these cases (with full-width characters and with word-wrapped lines). Program calculates (line1, column1) text position of column block left-top edge. Then program calculates (line2, column2) text position of column block right-bottom edge. Then program selects characters in range column1...column2 in all those affected lines line1...line2. And this program logic produces so weird look in word-wrapped mode.

How to replace from/to text containing line-breaks

There are several ways to perform it:

1. The simplest way: set multi-line mode in the Find/Replace dialog, using "+" button. Input fields will become tall and multi-line. To enter line-breaks there, press Ctrl+Enter.

2. Use plugin CudaExt:

  • Select fragment in editor (can contain line-breaks), "what to replace" .
  • Copy to clipboard the fragment (can contain line-breaks), which will be "replacement".
  • Call command in CudaExt plugin: "Replace all occurrences of selected string with clipbrd".

3. Search for selected editor text (can contain line-breaks) using command "find current selection, next".

4. Copy fragment (can contain line-breaks) which you need to find, to clipboard. Call command in CudaExt plugin: "Find clipbrd: next".

How to create macros and call them via toolbar

Q: I've used Boxer Editor for over a decade. Its strength is you can create macros that can be assigned to buttons that you can place onto the toolbar. I don’t know of any other text editors that can do that. ?

This can be done in CudaText like this:

  • Install plugin "Macros". Restart CudaText.
  • Use new menu "Macros" in the top menu, to record some macro(s). This will create command(s) "plugin: Macros: ..." in the Command Palette.
  • Install plugin "Config Toolbar".
  • Call config dialog via "Plugins / Config Toolbar / Configure buttons". In that dialog, add a button. In the button properties, choose your recorded macro command ("Choose command" button). This will add toolbar button for your macro. Customize this button as you wish (any icon, caption, tooltip).

Why XML document is not fully highlighted by XML lexer

Sometimes, you can see the poor syntax highlighting in XML documents. It is poorer than the "normal" highlighting in the "Lexer properties" dialog.

What is the reason? The reason is the blocking option

"lexer_folding_max_lines": 10000

You load the big XML document, with line count > 10k, and option blocks the "folding" in this document. It causes the lexer to miss folding ranges, and part of the syntax highlight depends on that (the angled brackets are still highlighted). You need to adjust that option to a bigger value.

Also note that CudaText has the "lite" lexer "XML ^", which is activated for too big XML files. The blocking option is:

"ui_max_size_lexer": 2

With the active "lite" lexer (when statusbar shows "XML ^"), syntax highlight is also not very rich, and there is no folding.

Troubleshooting the Windows shell extension for CudaText

There may be rare cases where CudaText's menu item shows up in Windows Explorer context menu but the entry's icon is missing and an error message states that the provided file name was not found.

File sets information

If you download a 32 bit version of CudaText, you will notice that there are two sets of files belonging to the shell extension.

Set 1 consists of these files:

  • CudaText_shell32.dll
  • install_shell32.cmd
  • uninstall_shell32.cmd

Set 2 consists of these files:

  • CudaText_shell64.dll
  • install_shell64.cmd
  • uninstall_shell64.cmd

Since 32 bit versions of CudaText can be run on both 32 bit and 64 bit versions of Windows, two sets of files are needed. Use set 1 if you run CudaText on a 32 bit version and set 2 if you run it on a 64 bit version of Windows.

The download package of CudaText 64 bit contains only set 2 since this version can only be run on a 64 bit version of Windows.

Please note: It is not possible to install the 32 bit version of the shell extension on 64 bit Windows or vice versa.

Common information

The context menu item works for all types of files, folders, disk drives, desktop links to these items, the desktop background and the background of an Explorer window showing a folder's content. Other kinds of right-clicked items don't show the context menu item.

The context menu entry's icon is extracted from the file "cudatext.exe", the absence of the icon indicates that "cudatext.exe" wasn't found by the shell extension. That's also the reason for the error message mentioned above.

Fixing installation error

Please note: In the following only the 64 bit version of the shell extension running on 64 bit Windows is dealt with. If you want to install the 32 bit shell extension on 32 bit Windows you have to select the appropriate file names.

In case a suitable item has been right-clicked and the icon is missing from the context menu item, it is possible to install the shell extension manually. To do that please follow the steps below.

At first ensure that all the files

  • cudatext.exe
  • CudaText_shell64.dll
  • install_shell64.cmd
  • uninstall_shell64.cmd

are stored in the same folder.

Start a Windows console with administrative permissions. If you don't know how to do that search the internet to learn it.

Use the "CD" command to navigate to the folder where the above files are stored (it should be your CudaText folder). You should end up with a command prompt that looks for example like this:


Type the following command into your console window and hit Enter:

regsvr32 /u "<Path-to-CudaText-folder>\cudatext_shell64.dll"

This uninstalls the failing shell extension. You should see a confirmation message that indicates a successful deregistration of the DLL.

Close all programs and log off or restart Windows. Login in again and ensure that the CudaText context menu item has disappeared.

Start a Windows console with administrative permissions again and use the "CD" command to navigate to your CudaText folder (the folder where the above files are stored).

Type the following command into your console window and hit Enter:

regsvr32 "<Path-to-CudaText-folder>\cudatext_shell64.dll"

You should see a confirmation message that indicates a successful registration of the DLL. Check the Explorer context menu to see if there is a CudaText menu item that has an icon. Right click for example a *.txt file and select "Open with CudaText" from the context menu.

Formats of files

Format of auto-completion acp file

Common auto-completion file format is ANSI text file, it contains list of lines in forms:

Type Id |Hint
Type Id (Param1; Param2; ...) |Hint
Type Id (Param1; Param2; ...): ResultType |Hint
  • Strings "Type", "Id", "Params", "Hint" are shown in separate columns of completion listbox, with separate colors. "Id" is the text which is inserted for a line.
  • Both ";" and "," chars can be params delimiters. "|Hint" part is optional.
  • If "\" char is present in hint part, then it must be escaped: "\\".
  • If space is needed in id part, it must be written as "%20" (it's allowed for any char in range 0x20..0x2F).

First line in the file can be the "control" line: it specifies what chars are "word chars" for the used syntax. For example, if word chars are minus, dot, and # sign, the control line should be:

#chars .-#

Format of install.inf files

User can open addons in zip files (using "File-Open") and install them. To make such zip file, pack into zip also "install.inf" with meta-info.

  • "title" field (required)
  • "desc" field, long text for install prompt dialog
  • "type" field (required) must be one of:
    • cudatext-plugin: to install plugin to subdir of "py" dir
    • cudatext-data: to copy any files into subdir of "data" dir
    • lexer: to install lexers (zip must be made by SynWrite's ExLexer addon)
    • lexer-lite: to install lite lexer
  • "subdir" field (required)
    • for plugins it should begin with prefix "cuda_"
    • for lexers it should be "-"
  • "homepage" field, source code repository URL (usually on GitHub)
  • "api" field, optional, minimal required API version (3 numbers dot-separated)
  • "os" field, optional, comma-separated list of supported platforms, described below

Install.inf supported "os" values

Value of "os" field is comma-separated list of platforms (no spaces around commas). Each platform is supported OS name, with optional trailing "-" and CPU family name.

OS names are:

  • win
  • linux
  • macos
  • freebsd
  • openbsd
  • netbsd
  • dragonfly
  • solaris
  • haiku

CPU families are:

  • i386
  • x86_64
  • arm
  • aarch64
  • sparc
  • ppc
  • ppc64
  • mips

So for example Windows x86 platform values are "win" and "win-i386", Linux AMD64 platform values are "linux" and "linux-x86_64".

Install.inf for plugins

Example of install.inf for plugin (plugin adds 2 menu items with menu separator between):

desc=Plugin allows smth

caption=MyPlugin\Cmd one


caption=MyPlugin\Cmd other

Section names: "item" followed by any string (e.g. "item1"). Fields in sections:

  • "section": possible values are "commands", "events".
  • "caption": caption of menu item in Plugins menu. "\" separates menu levels. "&" makes accelerator hotkey. "-" as final level name, makes separator menu item.
  • "method": Python method name in Command class.
  • "lexers": comma-separated lexer names, means that command can be run only when such lexer(s) active.
  • "hotkey": value must be simple hotkey string (e.g. "Alt+F", "Ctrl+Shift+F1") or key combo separated by "|" (e.g. "Alt+F|F|G").
    • If "lexers=" param missed, then hotkey saves to file "keys.json" for all lexers.
    • If "lexers=" param present, then hotkey saves to "keys lexer NNNN.json" for each mentioned lexer.
  • "menu": optional. Possible values:
    • "" (empty, default): menu item will be put to "Plugins".
    • "0": hide menu item.
    • "o": menu item will be put to "Options / Settings-plugins".
    • "op": menu item will be put both to "Plugins" and "Options / Settings-plugins".

Only for "section=events":

  • "events": comma-separated list of events to handle in plugin, e.g. "events=on_change,on_caret".
  • "keys": supported only for several events:
    • for "on_key": comma-separated list of int key codes to handle in event, e.g. "keys=9" means that event is only called for key code 9 (Tab char).
    • for "on_open" / "on_open_pre": comma-separated list of lower-case file extensions, without leading dot, to handle in event.

Install.inf sidebar buttons

CudaText can show plugin's sidebar buttons even without running the plugin in "on_start" event. Plugin should add sections "sidebar*" ("*" means any substring), with the keys:

  • "hint": Tooltip of button, must be the same as used by plugin to create its button.
  • "icon": Filename of PNG icon. If path is missed, CudaText uses file from its "data" folder. To specify filename in plugin folder, write value as "{dir}/subdir/filename.png" - with macro {dir}, with forward slashes.
  • "method": Python method name to show plugin panel. This command should create side panel for this button.

Plugin should add sections "bottombar*" ("*" means any substring) to perform the same, but for the bottom part of sidebar, where buttons "Console" and "Output" are placed.

Install.inf lexer lists

If plugin has many [itemN] sections, it is possible to set list of lexers using variable (not to write each time "lexers=name,name2,name3"). Declare list of lexers in [info] section like this, any variable name:


In [itemN] sections set lexers like this:


You can set lexers by reg-ex, e.g. reg-ex ".*SQL.*" means all names with substring "SQL". To do it, write variable with prefix:


Install.inf for data files

Example of install.inf for data files, to be copied into subdir of "data" dir. Name of subdir can be any, for example "themes".

desc=Nice Dark theme (by AuthorName)

Install.inf for lexers

To see example of install.inf for lexers, download any lexer. To see complex example, download lexer zip for "HTML Smarty" which has 2 lexers inside, one lexer is linked to another.

title=HTML Smarty

file=HTML Smarty internal
file=HTML Smarty
link8=HTML Smarty internal

Install.inf for lite lexers

Example of install.inf for lite lexer. Note that "^" suffix not needed here.


Format of .cuda-lexops files

Files keep lexer styles, which user changed in the "Lexer Properties" dialog. JSON format.

Root keys:

  • "files": str: space-separated list of file masks for lexer. Each mask can be "nnn" for extension .nnn, or "/mmm" for full filename mmm.
  • "style_NN" for each lexer style name "NN", which user have changed. Subkeys are:
    • "font_color": str: color of font, in Pascal format.
    • "font_style": str: several chars: "i" for italic, "b" for bold, "s" for strikeout.
    • "back": str: color of background, in Pascal format.
    • "brd_c_l", "brd_c_r", "brd_c_t", "brd_c_b": str: color of border (left, right, top, bottom), in Pascal format.
    • "brd_t_l", "brd_t_r", "brd_t_t", "brd_t_b": int: type of border (left, right, top, bottom). Values 0..9: None, Solid, Dash, Dot, DashDot, DashDotDot, Solid2, Solid3, WavyLine, Double.

Color in Pascal format: hex number (6..8 digits) with "$" prefix, or constants. See possible constants (with hex values) in Lazarus file Graphics.pp, where string 'clBlack' is defined. https://gitlab.com/freepascal.org/lazarus/lazarus/-/blob/main/lcl/graphics.pp


CudaText vs Sublime Text, different answers to questions

How to call external programs/compilers?

ST3: Use feature of editor called "build systems".

CudaText: Use plugin "External Tools", which adds "Tools" item to the top menu. Or: use plugin "Runner". Both plugins are described here: CudaText_plugins.

How to change settings for one OS only?

ST3: You need to use platform-specific config files. E.g. for macOS, platform-specific config is "Preferences (OSX).sublime-settings".

CudaText: You need to use the config user.json, but write there options with OS specific suffixes. E.g. Windows option is "font_name", and macOS option is "font_name__mac". Possible suffixes are listed in default.json: __linux, __mac, __freebsd etc. Only limited count of options support OS suffixes, this is marked in the default config (default.json).

How to change settings for one syntax only?

ST3: To edit syntax-specific config, call "Preferences / Settings - Syntax Specific".

CudaText: To edit lexer-specific config, see #Configs.

How to add commands to top/context menu?

ST3: You need to create *.sublime-menu files: https://www.sublimetext.com/docs/3/menus.html#available_menus

CudaText: You need to install plugin "Configure Menu". In its dialog, create "menu.json" file which has default items of top menu and context menu. Then edit that file.

How to find/replace text in many files?

ST3: Use built-in command "Find in files".

CudaText: Use plugin FindInFiles. It has 2 major versions: v3 is frozen, and new v4 is evolving.

How to find file in a project?

ST3: Use "Goto Anything" (Ctrl+P on Windows/Linux, Command+P on macOS).


  • To find file by name, use command "Plugins / Project Manager / Go to file...". After file is focused in project, press Enter to open it.
  • To find file by contents, use plugin FindInFiles (v3) which allows to search in project files. Quote from its help:
Set special value "<Project Folders>" (in short <p>) for field "In folder" to search in project files.

How to show vertical lines on some columns?

ST3: Use option

"rulers": [40, 80, 120],

CudaText: Use option

"margin_string": "40 80 120",

How to highlight pair brackets?

ST3: Brackets highlight is built-in feature, turned on by default.

CudaText: Brackets highlight is built-in, but it's off by default. Use several "bracket_" options, see comments in the "Options Editor" plugin.

How to highlight pair HTML tags?

ST3: Use plugin, e.g. https://packagecontrol.io/packages/BracketHighlighter

CudaText: Use options for "dynamic highlighting", "lexer_dynamic_" in "Options Editor" plugin.

How to add custom syntax support?

ST3: You need to create syntax file, https://www.sublimetext.com/docs/3/syntax.html

CudaText: You need to create lexer, see #Lexers.

How to customize hotkeys?

ST3: You need to edit keybinding files like "Default (Windows).sublime-keymap".

CudaText: In the Command Palette dialog, focus needed command item, press F9 - additional dialog will appear to set the hotkey. Method 2: install plugin "Configure Hotkeys" which gives alternative dialog.

How to use Emmet?

ST3: Install plugin "Emmet". Emmet here is written in JavaScript.

CudaText: Use pre-installed plugin "Emmet". Emmet here is written in Pascal with minor differences (e.g. "lorem" works differently).

How to show 2/3/4 files at once?

ST3: Use "View / Layout" menu.

CudaText: Use "=" item in the top menu.

How to split window for single file?


  • menu "File / New View into File"
  • menu "View / Layout / Columns: 2 (or Rows: 2)"
  • drag the tab into another group

CudaText: menu "View / Split tab / Toggle split".

How to detect syntax by first line of file?

ST3: It's configured in syntax file: https://superuser.com/questions/752025/sublime-text-3-detect-syntax-based-on-file-header

CudaText: Use config described in #Detection_by_first_file_line.

How to assign syntax to undetected file extension?

ST3: Open your file, click statusbar item for syntax, use item "Open all with current extension as...".

CudaText: Use "file types config", see #File_types_config.

How to select several occurrences of a word?

ST3: Use command "Selection / Expand selection to word".

CudaText: Use command "Selection / Add next occurrence of selected word".

There is a difference in CudaText implementation: CudaText command first checks, is first selection 'whole word' or not. If it's whole word, command adds selections which must be also whole words. In ST, command does not check 'whole word' state of next selections. You may switch to ST behaviour. How? CudaText "Command Palette" gives two commands:

  • A: add next occurrence of selected word
  • B: add next occurrence of selected text (not whole-word)

You can reassign hotkey from the command A to the command B, so hotkey will give the behaviour of Sublime Text.

How to select all occurrences of a word?

ST3: In the Find dialog, enter a word, check "whole words", press "Find All".


  • In the Find dialog, enter a word, check "whole words", press "Select all".
  • Plugin "Highlights Occurrences" gives command "Select all occurrences".

How to record macros?

ST3: Use menu items in the "Tools" menu.

CudaText: Install plugin "Macros", which adds item "Macros" to the top menu.

How to use "Go to symbol"?

ST3: Use menu item "Go to symbol".

CudaText: It doesn't have "Go to anything" but it has "Go to symbol" for a lexer, if lexer finds such symbols for Code-Tree. Install plugin "CudaExt", which gives menu "Plugins / Cuda-Ext / Code-Tree" with several menu items. One item is "Symbols list" which shows Code-Tree items in the menu dialog.

How to switch between C++ header/implementation files?

ST3: Use command "Switch header/implementation".

CudaText: Use plugin "Switch Header" (it's not only for C++, it's configurable for all lexers).

How to jump to next/previous modified lines?

ST3: Use commands "Next modification", "Previous modification".

CudaText: Use plugin "CudaExt" which gives commands:

  • "Jump: to next/previous changed lines",
  • "Jump: to next/previous working lines",
  • "Jump: to next/previous saved lines".

See #Line_states.

How to detect indentation characters in a file?

ST3: Menu item "View / Indentation / Guess settings from buffer".

CudaText: Plugin "Detect Indent" which does the same.

How to change indentation characters in a file?

ST3: Click statusbar cell "Tab size..."/"Spaces...", it has menu items "Convert indentation to spaces", "Convert indentation to tabs".

CudaText: The same as for ST3.

How to install plugins without package manager?

ST3: Open terminal, go to Packages folder, run "git clone" in that folder, or copy plugin there.

CudaText: Open terminal, go to "py" subfolder, run "git clone" in that folder, or copy "cuda_" plugin folder there.

How to make vertical/column selection?

ST3: See the official documentation page "Column Selection".


  • Mouse shortcuts: #Mouse shortcuts.
  • Keyboard commands: "column select: up / down / left / right / ....".
  • Click the statusbar cell "-", it will toggle to "||", and usual mouse selection will perform column selection.

How to swap line up/down

ST3: Commands "Edit / Line / Swap Line Up/Down".

CudaText: Commands "Edit / Line operations / Move line(s) up/down".

How to show menu of tabs, project files, symbols

ST3: "Goto anything" (Ctrl+P) for all stuff.


  • List of opened tabs: command "ui: switch tab, dialog".
  • List of files in the current project: "plugin: Project Manager: Go to file".
  • List of "symbols" in the current document: "plugin: Cuda-Ext: Code-Tree: Symbols list" (shows the same symbols as code-tree can show).

How to use 'atomic saving'

'Atomic' file saving is saving to a temporary file, then renaming that file to the destination. 'Atomic' saving is not implemented in CudaText, because users of Sublime Text 3 consider it as harmful feature.

  • It drops extended file attributes (on NTFS on Windows; Unix-like have similar problem too?)
  • It drops NTFS file streams, on Windows
  • Problems with files located on Network drives, on Windows
  • Problems with symlinks
  • It needs additional options like "on which drives to use atomic saving"