macOS Open Sesame

This article applies to macOS only.

See also: Multiplatform Programming Guide

The macOS /usr/bin/open command is a veritable Aladdin's cave of utility. The command opens a file (or a directory or URL), just as if you had double-clicked the file's icon. If no application name is specified, the default application as determined via LaunchServices is used to open the specified file. If the file is in the form of a URL, the file will be opened as a URL. See Executing External Programs to run the command from within your application.

Opening files

Want to open a test.c file?

  open test.c

Want to open your test.c file with TextEdit and not with Xcode?

  open -a TextEdit test.c

or

  open -e test.c

Opening directories

Want to open Finder at a particular directory, say the user's Documents directory?

  open ~/Documents

Opening URLS

Open our favourite website:

  open https://wiki.freepascal.org

Safari not your favourite? Use FireFox maybe:

  open -a FireFox  https://wiki.freepascal.org

Opening applications

Want to open another copy of a running application? Normally macOS would simply bring the already-running application to the foreground, but:

  open -n -a TextEdit

Want the open command to wait until the application opened has exited?

  open -W -n -a TextEdit

Opening Preference Panes

Want to open the Security Preferences Pane?

  open "x-apple.systempreferences:com.apple.preference.security"

How about the Firewall tab of the Security Preferences pane?

  open "x-apple.systempreferences:com.apple.preference.security?Firewall"

Note that this scheme was new in Yosemite (macOS 10.10) and that Apple subsequently restricted use of the URL scheme in El Capitan (macOS 10.11).

See: Apple: System Prefs Links

More options

For the full gamut of open command options, open a Terminal and call up the Unix man page:

 man open

See also (cross-platform)

• OpenDocument
• OpenURL