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I'm attempting to follow the instructions for pinning startup tabs in Chrome. On OS X how do I add command line arguments to items that persist in my dock?

2 Answers 2

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You have basically two options:

Option 1: Use Automator to create an application that in effect launches Chrome with command line arguments.

Start Automator and select to create an Application. Double-click Run Shell Script in the Library/Utilities folder and replace the text content — cat — with the following:

open -a "Google Chrome.app" --args -pinned-tab-count=4
# keep the .app suffix or will break with Parallels

Save anywhere you like.

To replace this application's icon, Get Info on your real Google Chrome, click on the icon on the top left, press Cmd-C, Get Info on your Chrome Automator app, click the icon, and press Cmd-V.

Since it's a different application, the Dock will display two Chrome applications when it's running: Chrome, and your Chrome launcher.


Option 2: Edit your application bundle to launch a script instead. This script will start the actual application, adding the command line argument.

Right-click Google Chrome.app and select Show Package Contents. Go to Contents/ and open Info.plist in Property List Editor/Xcode (Apple's developer tools), or a third party plist editor.

Look for the entry CFBundleExecutable or Executable File. Remember its value (e.g. firefox-bin for Firefox). Replace it with parameterized-app.sh.

Open Terminal and enter the following:

touch /Applications/Firefox.app/Contents/MacOS/parameterized-app.sh
open /Applications/Firefox.app/Contents/MacOS/parameterized-app.sh

An editor for the .sh file will open. Set the contents of the file to:

#!/usr/bin/env bash
exec /Applications/Firefox.app/Contents/MacOS/firefox-bin -ProfileManager

(using the actual executable's name you removed from Info.plist, adding the desired command-line arguments)

Save and close. In Terminal, enter the following:

chmod +x /Applications/Firefox.app/Contents/MacOS/parameterized-app.sh

Now, close Terminal and move your application (which must not be running right now) to a different folder and back again. This will update Launch Services, otherwise your changes will be ignored and irritate you immensely.

Now, when you open your application, it will actually execute the .sh file, which will in turn launch the actual executable file, sending the command line args along.

It will look and behave like you expect it to, but you will need to repeat this whenever you update your application, as this will generally replace the application bundle and all the changes you made.

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    "move your application to a different folder and back again" should be bold - completely missed it on first read :)
    – stephanos
    Oct 27, 2013 at 10:14
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    Is there a way to update/reset/restart Launch Services via a shell command so that you don't have to move the application out and back again? i.e. so that that step is easily scriptable? Apr 10, 2014 at 16:45
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    @Jordan Brough You can use the lsregister utility to force a LaunchServices update: /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -f /Applications/Hello\ World.app
    – paxswill
    Nov 29, 2014 at 16:29
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    Of course, Option 2 only works on non-CodeSign apps. If it comes from apple or the app store, it's signed against changes. Even a change to Info.plist will stop it. In that case, a simple stub/wrapper app would help.
    – cde
    Oct 2, 2015 at 20:32
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    I tried the first technique using open with Thunderbird and needed to add -n ("Open a new instance of the application(s) even if one is already running."): open -n -a "Thunderbird.app" --args --new-instance -P profile-name This is in Mojave. Apr 23, 2019 at 22:59
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You could write a script that launches Chrome, but that wouldn't be the application icon in the dock, and it would cause a separate Chrome icon to appear. So you'll have to create an application package.

First, make a copy of your Chrome app. Then, there are two approaches that might work; I'm not sure which will play better with Mac OS X and/or Chrome's self-update.

  1. Make a 'launcher' that just calls Chrome with the arguments.

    • Open the app package (right-click → Show Package Contents in the Finder), and throw out everything but Info.plist, PkgInfo, and MacOS.
    • In the MacOS folder, delete the “Google Chrome” executable and replace it with a shell script that calls the real Chrome:

      #!/bin/sh
      exec '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome' -pinned-tab-count=4
      

      Don't forget to chmod +x the script.
       

  2. Modify the Chrome package you actually run.

    • In the MacOS folder, rename “Google Chrome” and write a shell script which invokes the real thing with the extra arguments:

      #!/bin/sh
      exec '/Applications/My Modified Google Chrome.app/Contents/MacOS/Google Chrome-real' -pinned-tab-count=4
      
    • I see the Chrome package has something about code signing; you might need to delete the CodeResources and/or _CodeSignature to get it to run with these changes.

This is all based on my understanding of Mac app packages; I haven't actually tested these changes on Chrome in particular. It is even posible that the Chrome executable on Mac doesn't support this option, as Mac applications are generally not expected to be run with controllable command-line options (unlike, for example, Windows, where applications are normally launched via shortcuts which can have embedded options).

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  • Chrome support parameters, I just automated mine following your instruction #2. You do indeed need to specify the full path for the binary, and don't forget to chmod 755 Google\ Chrome (your script) after you've finished. I actually named my script launch.sh and symlinked it to Google\ Chrome for ease of updates. May 25, 2015 at 13:14
  • Note that modifying package contents causes problems with code signing, resulting in odd problems like https not working properly: bridge.grumpy-troll.org/2011/01/…
    – drevicko
    Jul 5, 2019 at 1:47

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