0x09

I have a script that shouldn't be run as anybody other than the "nobody" user if it's in production mode, since it will overwrite files with the wrong permissions otherwise. My colleague Ben Tucker alerted me to Process.uid, which allows me to do something like

$ /home/ian/sw/bin/ruby -e "puts Process.uid == `id -u nobody`"
false
$ sudo -u nobody /home/ian/sw/bin/ruby -e "puts Process.uid == `id -u nobody`"
true

The rest should be trivial.