Writing Idempotent Scripts

Summary

A script is idempotent if running it multiple times produces the same result as running it once — critical for automation scripts and infrastructure code that might be re-run after a partial failure.

• 1Take a script you've written and check whether running it twice causes an error or duplicate effect.
• 2Practice adding a check-before-act pattern (e.g. 'if this doesn't exist, create it') to make a script idempotent.
• 3Learn why idempotency matters even more for infrastructure automation than for one-off scripts.