I created a "system" user in Ubuntu 11.04 (adduser --system) for running certain cron jobs, but sometimes I want to test things out by manually running commands as that user. What's the easiest way to do this?

su doesn't work, because the user has /bin/false as its shell (which is fine for cron). I've been manually changing the shell to /bin/bash to do my testing and then changing it back again, but I wonder is there an easier way?

2 Answers 2


I use su - targetuser -s /bin/bash from a root shell.

For direct command execution use -c:

su - targetuser -s /bin/bash -c "/bin/echo hello world" 
  • 1
    That works, thanks! How did I miss the -s option?
    – EMP
    May 28, 2011 at 3:54
  • 3
    you can also tack on a -c "your_command_here" option to pass the command you'd like to run versus waiting for the shell and then typing it at a new prompt.
    – dmourati
    May 28, 2011 at 6:16

Use sudo. This will work even if the user doesn't have a real shell.

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