app.py

#!/bin/env python

from sys import argv, exit, stdin

argv[1:] or exit('no mode specified')

mode = argv[1]

apps = {
    'minecraft':'/bin/minecraft',
    'mumble':   '/bin/mumble',
    'steam':    '/bin/steam',
    'tf2':      '/bin/steam -applaunch 440 -w 1920 -h 1080 -novid -sw -noborder -noforceparms -console -nocrashdialog'
}

print({
    'write': lambda: '\n'.join(apps.keys()),
    'read': lambda: apps.get(stdin.readlines()[0].strip()) or exit('app not found')
}.get(mode, lambda: exit('invalid mode'))())