Launchctl Start Interval

Question

I know when using a plist in the launch daemons folder there is a key called <StartInterval>. I much prefer using launchctl when I can because it is a lot quicker then writing out a whole plist, but I have not been able to figure out how to get the process to restart after it has been killed. I have already read the man page and haven't found anything there. Is there a way? Typically I use the following command:

launchctl submit -l somename -p /path/to/script -o output.txt -e errors.txt

But that will not restart the program if it is killed after any time interval.

Answer 1

launchctl submit should already run the program again if it terminates for some reason:

 submit -l label [-p executable] [-o path] [-e path] -- command [args]
          A simple way of submitting a program to run without a configura-
          tion file. This mechanism also tells launchd to keep the program
          alive in the event of failure.

          -l label
                   What unique label to assign this job to launchd.

          -p program
                   What program to really execute, regardless of what fol-
                   lows the -- in the submit sub-command.

          -o path  Where to send the stdout of the program.

          -e path  Where to send the stderr of the program.

To run a program again if it exits with an error, set the SuccessfulExit criteria for KeepAlive to false:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>test</string>
  <key>ProgramArguments</key>
  <array>
    <string>bash</string>
    <string>-c</string>
    <string>n=$((RANDOM%2));say $n;exit $n</string>
  </array>
  <key>KeepAlive</key>
  <dict>
    <key>SuccessfulExit</key>
    <false/>
  </dict>
  <key>StartInterval</key>
  <integer>60</integer>
</dict>
</plist>

launchd throttles jobs so it takes about 10 seconds for the program to respawn.