How to change application run command when started from Dock

dock

In Windows, you can edit an application shortcut and change the shortcut's target. How do you do this in Mac OS?

For example, I want to change my Chrome application to do verbose logging, by appending this to the run command: --enable-logging --v=1.

Best Answer

You can use Automator or AppleScript to make an app that launches the app with specific arguments:

-- Applescript version
do shell script "open -a 'Google Chrome' --args --enable-logging --v=1"

Or you can go into the app bundle and modify the Info.plist, changing CFBundleExecutable from (for example) "Google Chrome" to the name of a new wrapper script that you put in MacOS. Here's a Python script that automates that for you (It actually makes a new app with symlinks). Run it with python linkapp.py<path to actual app> <where to put new app> in Terminal. When it asks you whether to create a wrapper script, answer y.

(the script is now on GitHub, but I'll try to keep this one updated)

#!/usr/bin/env python

import sys
import os
import shutil
import subprocess
import re

WRAPPER_SCRIPT = '''\
#!/usr/bin/env bash
executable="$(dirname "$0")/%s"

# add flags here.
"$executable" 
'''

def printerr(message):
    sys.stderr.write("\033[1;31m" + message + "\033[0m")

def link_item(item):
    os.symlink(os.path.join(bundle_contents_path, item),
               os.path.join('.', item))

def replace_executable(filename, new_executable):
    old_executable = subprocess.check_output(['defaults', 'read', os.path.abspath(filename), 'CFBundleExecutable'])
    old_executable = old_executable.rstrip()
    subprocess.call(['defaults', 'write', os.path.abspath(filename), 'CFBundleExecutable', new_executable])
    return old_executable


if len(sys.argv) <= 2:
    printerr("Usage: linkapp.py <app-bundle> <new-place>\n")
    exit(1)


bundle_path = os.path.abspath(sys.argv[1])
bundle_contents_path = os.path.join(bundle_path, 'Contents')
new_contents_path = os.path.abspath(os.path.join(sys.argv[2], 'Contents'))
os.makedirs(new_contents_path)

# loop through the app bundle and symlink everything
#                                        (except Resources, MacOS & Info.plist)
os.chdir(new_contents_path)
for i in os.listdir(bundle_contents_path):
    if i.lower() != 'info.plist':
        if i.lower() in ['resources', 'macos']:
            os.makedirs(i)
            for j in os.listdir(os.path.join(bundle_contents_path, i)):
                link_item(os.path.join(i, j))
        else:
            link_item(i)

# just copy Info.plist for easy editing
shutil.copy(os.path.join(bundle_contents_path, 'Info.plist'), new_contents_path)
subprocess.call(['plutil', '-convert', 'xml1', 'Info.plist'])

printerr("Create wrapper script [y/n]? ")
ans = sys.stdin.read(1)
if ans.lower() == 'y':
    os.chdir('MacOS')

    wrapper_script_file = 'run_with_specified_arguments.sh'

    original_executable = replace_executable('../Info.plist', wrapper_script_file)

    with open(wrapper_script_file, 'w') as f:
        f.write(WRAPPER_SCRIPT % original_executable)
    os.chmod(wrapper_script_file, 0755)

    subprocess.call(['open', '-R', wrapper_script_file])
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