Avoid Rogue Shell Scripts: Logging, Usage, Locking, and Documentation Tips

This article, compiled from a DevOpsDays presentation, shares practical tips for writing robust shell scripts that avoid common pitfalls in operations work.

Logging Function

Adding a dedicated logging function (e.g., shell_log) lets you record when a script starts, finishes, and any intermediate events, which is essential for tracking MySQL backup times.

[root@linux-node2 shell]# catshell_template.sh.log
2016-08-27 06-01-19 : shell_template.sh :shell beginning ,write log test
2016-08-27 06-01-19 : shell_template.sh :shell success ,write log test

Usage Help

Providing a usage function ( shell_usage) informs users how to run the script and what arguments are accepted, preventing accidental execution of destructive commands.

[root@linux-node2 shell]# ./shell_template.sh
Usage: ./shell_template.sh {backup}

File Locking

To prevent concurrent executions, implement shell_lock and shell_unlock which create and remove a lock file. If the lock exists, the script exits, avoiding overlapping runs.

Documentation and Comments

Include clear comments and author information at the top of the script so future maintainers understand its purpose and origin.

These three techniques—logging, usage help, and locking—significantly improve the professionalism and safety of shell scripts used in daily operations.