Macos – Command-line controllable alarm clock programs for Mac OS X

Here's my best solution: Create an Applescript with:

do shell script "/Applications/Firefox.app/Contents/MacOS/firefox -P default -no-remote & killall Firefox.app"

And save it as an application.

You can put whatever application with whatever args in the first part. The part after the & needs to kill whatever you have named your script + .app. You'll see the script app flash up in the dock, but it will then disappear.

Note: The script will not work properly when run from Script Editor, only when run from the script application you have created.

In bash, detach is a built-in, used as follows:

emacs &
detach %+ # or % + the number in brackets printed after the above

In zsh, you can background and detach in a single operation:

emacs &|