Bash Scripting

Preventing duplicate cron job executions

I feel like sometimes cron jobs create more problems than they solve. It’s not the fault of cron, but rather the jobs being executed. This is especially true when the jobs result in duplicate running instances like the following example. $ ps -elf | grep forever 4 S vagrant 4095 4094 0 80 0 - 1111 wait 21:59 ? 00:00:00 /bin/sh -c /var/tmp/forever.sh 0 S vagrant 4096 4095 0 80 0 - 2779 wait 21:59 ?

8 Tips for creating better bash scripts

When I was first got started with administrating Linux and Unix servers I was working in an environment where there were tons of adhoc scripts that other admins wrote. From time to time I would find myself troubleshooting why one of those scripts suddenly stopped working. Sometimes the scripts would be well written and easy to understand, other times they were clunky and confusing. While troubleshooting the poorly written scripts was always a hassle at the time, it taught me an important lesson.