tldr/pages/common/shellcheck.md

# shellcheck

> Statically check shell scripts for errors, usage of deprecated/insecure features, and bad practices.
> More information: <https://github.com/koalaman/shellcheck/wiki>.

- Check a shell script:

`shellcheck {{path/to/script.sh}}`

- Check a shell script interpreting it as the specified shell dialect (overrides the shebang at the top of the script):

`shellcheck {{[-s|--shell]}} {{sh|bash|dash|ksh}} {{path/to/script.sh}}`

- Ignore one or more error types:

`shellcheck {{[-e|--exclude]}} {{SC1009,SC1073,...}} {{path/to/script.sh}}`

- Also check any sourced shell scripts:

`shellcheck {{[-a|--check-sourced]}} {{path/to/script.sh}}`

- Display output in the specified format (defaults to `tty`):

`shellcheck {{[-f|--format]}} {{tty|checkstyle|diff|gcc|json|json1|quiet}} {{path/to/script.sh}}`

- Enable one or more [o]ptional checks:

`shellcheck {{[-o|--enable]}} {{add-default-case,avoid-nullary-conditions,...}} {{path/to/script.sh}}`

- List all available optional checks that are disabled by default:

`shellcheck --list-optional`

- Adjust the level of severity to consider (defaults to `style`):

`shellcheck {{[-S|--severity]}} {{error|warning|info|style}} {{path/to/script.sh}}`