Question

I have been using a custom Linux Kernel 3.2.1 on a machine running Ubuntu 12.04 for some time, and today I wanted to schedule a cron task and realized that crons in the crontab are not being executed.

The cron service is running, so I believe it might be a problem with some kernel configuration option I missed, but don’t figure out what may be. Any suggestion?

Answer 1

I don’t think a custom kernel would make that much difference. Maybe… but not the first thing I’d look at.

First, check if the user the cron is running under has local mail (check in /var/spool/mail/). If there is an error, it may be written there. If not, try redirecting the stderr and stdout of your program to a file. E.g. add to your cron:

SHELL = /bin/bash
PATH = /usr/bin/:/bin

* * * * * ls /tmp > $HOME/ls_tmp.log 2>&1

I think the default shell for cron on ubuntu is sh rather than bash, so I like to set it to bash to avoid bash/sh issues. I also like to be explicit about the path (and will add ~/bin to the start of it, for my local scripts).