Running mac os x application as a user does not stop by its own

Question

I am creating a macOS installer package.

For this I am using a post-install script file that launches an application and then loads a LaunchDaemon plist.

Here is the post-install script:

#!/bin/bash

cd /usr/local/TestApp
USER_NAME=$(who | head -1 | head -1 | awk '{print $1;}')
sudo -u $USER_NAME /usr/local/TestApp/Test.app/Contents/MacOS/Test -l

sudo launchctl load /Library/LaunchDaemons/com.testapp.plist

The result is that it starts the application with the sudo -u $USER_NAME /usr/local/TestApp/Test.app/Contents/MacOS/Test -l command and then blocks, because the application keeps running.

Therefore, the script gets stuck, and the LaunchDaemon is never loaded.

Please let me know what I can do this in case.

Answer 1

If you simply want to launch a Mac application (*.app) asynchronously,

• use open -a with the bundle directory path (ending in .app)
• and pass any pass-through command-line arguments after --args (see man open):

sudo -u $USER_NAME open -a /usr/local/TestApp/Test.app --args -l

^{See note at the bottom re reliably determining $USER_NAME, the invoking user's username.}

If, for some reason, you do need to target the executable embedded in the *.app bundle directly, you must use Bash's & control operator to run the command in the background:

#!/bin/bash

# Get the underlying username (see comments below).
userName="${HOME##*/}"

# Launch the app in the background, using control operator `&`
# which prevents the command from blocking.
# (Given that the installer runs the script as the root user,
# `sudo` is only needed here for impersonation.)
sudo -u "$userName" /usr/local/TestApp/Test.app/Contents/MacOS/Test -l &

# Load the daemon.
# (Given that the installer runs the script as the root user,
# `sudo` is not needed here.)
launchctl load /Library/LaunchDaemons/com.testapp.plist

Note that I've changed the way that the underlying username is determined:

• ${HOME##*/} extracts the last path component from $HOME, the underlying user's home directory path, which reflects the user who invoked the installer.

• This is more robust than using who without arguments, whose output can include other users.

(As an aside, who | head -1 | head -1 | awk '{print $1;}' can be simplified to the more efficient who | awk '{print $1; exit}).