Run a shell script periodically on Mac OS X without root permission

bash, cron, launchd, macos, startup

Solution

Any particular reason you don't want to use a normal crontab?

% echo "* * * * * /Users/paul/Desktop/1.sh" | crontab -

This command should add a cron job that runs once per minute.

NOTE that this command will also replace any crontab that you already have. The `crontab -` command should be used with caution, as a short-cut.

If you want to edit an existing crontab, so as to avoid obliterating previously set jobs, you can use `crontab -e`. (If it launches `vim` and you don't know how to use `vim`, you can exit by hitting ESC:q!Enter and then go find editor documentation.)

If you want instructions on how to edit crontabs, type `man crontab` at your shell. If you want syntax information on the crontab file, `man 5 crontab` will show you that.

Enjoy!

UPDATE: (per comments)

To run your job every 30 seconds requires a simple hack. Cron only runs jobs on a per minute basis, so to run things every 30 seconds, you can have two jobs, one of which has a 30 second delay. For example:

  #Mn Hr Da Mo DW Command
  *   *  *  *  *   /Users/paul/Desktop/1.sh
  *   *  *  *  *   sleep 30; /Users/paul/Desktop/1.sh

Hope this helps.

Problem

Original source