Linux infinite loop with background - linux

Question

I have a little script called "CheekyScript.sh" that looks something like this:
#!/bin/bash
nohup mvn run_something_pretty_long
This clearly work pretty fine as it starts a long process in the background that continues running after the session has expired and the user has logged out.
What I wish to achieve is pretty simple, introduce a little infinite loop, to this process is being ran over and over again but only AFTER the nohup is completed. Of course I still wish this entire bash script and the nohup within to run long after the session expired and I'm logged out.
I was thinking something similar:
#!/bin/bash
while true
do
nohup mvn run_something_pretty_long
sleep 60
done
Obviously is what this does is that it starts the nohup process every 60 seconds. The desired thing would be wait for the nohup, wait a minute and start the loop again.
I was wondering what is the best practice solution for something like this?
Thank you very much in advance.

Answer 1

use crontab
add an entry like this
1 * * * * /path/to/something
In the something script
#!/bin/bash
LOCKFILE=/var/lock/mvn.lock
[ -f $LOCKFILE ] && exit 0
# Upon exit, remove lockfile.
trap "{ rm -f $LOCKFILE ; exit 255; }" EXIT
touch $LOCKFILE
mvn run_something_pretty_long
exit 0
This tries to run the script once a minute and mostly fails as the lockfile exists. But if the script is finished the lockfile isn't there and it starts again
By default cron emails all output to the user that owns the job

Answer 2

You want to run your long running script either once, or repeatedly. And you want to run both of these using nohup. Since you already have one script that handles the first (run once) case, make two copies of your "CheekyScript.sh". The first one runs once, and the second you edit to run repeatedly (and can optionally check for a done condition).
This one runs once,
#!/bin/bash
#CheekyScriptOnce.sh
nohup mvn run_something_pretty_long
This one runs repeatedly,
#!/bin/bash
#CheekyRepeat.sh
thing="mvn run_something_pretty_long"
delay=60;
nohup (while [ 1 ] ; do $thing; sleep $delay; done)
But you want some way to signal done. A control file can handle that,
#!/bin/bash
#CheekyRepeatConditional.sh
thing="mvn run_something_pretty_long"
delay=60;
if [ ! -d etc ] ; then mkdir etc; fi
touch etc/Cheeky.run
nohup (while [ -f etc/Cheeky.run ] ; do $thing; sleep $delay; done)