To associate Terminal with .sh files, without using Finder to change a preference

In most cases, all that's required should be possible from the command line …

Preparation

Two commands:

defaults read com.apple.LaunchServices | grep -B 1 -A 3 public.shell-script

defaults read com.apple.LaunchServices | grep -B 1 -A 4 "LSHandlerContentTag = sh;"

If either command reveals an existing preference

Use Xcode or any other suitable property list editor to remove the relevant dictionary from the LSHandlers key within the following file:

~/Library/Preferences/com.apple.LaunchServices.plist

Hints:

• command line removal of a single dictionary from an array may be unnecessarily difficult
• removal should be necessary only if (say) the user has previously used Finder to associate .sh files with an application other than the system default.

Adding to LaunchServices preferences, for Terminal to view and edit .sh files

Two one-line commands.

Depending on your requirements, the first command alone may suffice:

defaults write com.apple.LaunchServices LSHandlers -array-add '{ LSHandlerContentType = "public.shell-script"; LSHandlerRoleViewer = "com.apple.Terminal"; LSHandlerRoleEditor = "com.apple.Terminal"; }'

defaults write com.apple.LaunchServices LSHandlers -array-add '{ LSHandlerContentTag = "sh"; LSHandlerContentTagClass = "public.filename-extension"; LSHandlerRoleViewer = "com.apple.Terminal"; LSHandlerRoleEditor = "com.apple.Terminal"; }'

For the new preferences to be respected

First attempt, an experiment

After editing the .plist I tried logging out of the system, then logging in. This did not have the desired effect.

Second attempt

Maybe not the best approach for modern releases of the system, these two commands seem effective:

/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill

/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -seed -v

• option -v only if you want a verbose view of progress.

After the scan completes — after the Launch Services database has been seeded — you should find that .sh files open in Terminal in response to an open command.

Probably best

The accepted answer to Super User question Is there a faster way to change default apps associated with file types on OS X? suggests:

• Requires restarting the OS to apply changes (logging out and back in isn't enough)

A question arises: Why is a command line change to ~/Library/Preferences/com.apple.LaunchServices.plist not effective immediately?

Background

Understanding Terminal.app support for .sh (public.shell-script)

Consider the result of the following command:

defaults read /Applications/Utilities/Terminal.app/Contents/Info

• under CFBundleDocumentTypes (an array of dictionaries describing the document types supported by the bundle) we see that Terminal is designed to support com.apple.terminal.shell-script

• public.shell-script (the system-declared UTI associated with .sh) is not supported at that level, it appears elsewhere in the property list — under UTExportedTypeDeclarations

Credit

To Daniel Beck for his Super User answer under How to change default app for all files of particular file type through terminal in OS X?.