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 [s]hell dialect (overrides the shebang at the top of the script):

shellcheck --shell sh|bash|dash|ksh path/to/script.sh

• Ignor[e] one or more error types:

shellcheck --exclude SC1009,SC1073,… path/to/script.sh

• Also check any sourced shell scripts:

shellcheck --check-sourced path/to/script.sh

• Display output in the specified [f]ormat (defaults to tty):

shellcheck --format tty|checkstyle|diff|gcc|json|json1|quiet path/to/script.sh

• Enable one or more [o]ptional checks:

shellcheck --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 [S]everity to consider (defaults to style):

shellcheck --severity error|warning|info|style path/to/script.sh