Run ShellCheck on a shell script to find bugs, stylistic issues, and potential errors. Use when: reviewing shell scripts, validating CI pipeline scripts, or debugging script errors. Prefer over: manual bash syntax inspection when you want automated rule-based analysis (300+ rules). Avoid when: checking many large scripts — run ShellCheck locally for bulk analysis.

Supported shells: bash, sh, dash, ksh, ash

Returns structured JSON with issue details including line, column, code, message, and severity.

Common error codes:

• SC1090: Can't follow non-constant source

• SC2148: Tips depend on target shell and yours is unknown

• SC2086: Double quote to prevent globbing

• SC2164: Use cd with || exit

• SC2006: Use $(...) instead of legacy backticks

• SC2029: Note that, unlike in BASH, a variable cannot contain a newline

• SC2230: Which is redundant

• SC2068: Double quote array subscript

• SC2196: Several way to test global flag

• SC2001: See if you can use ${var//search/replace}

• SC2162: read without -r will mangle backslashes

• SC2129: Style: Consider using { cmd1; cmd2; } >> file instead of individual redirects

Use exclude parameter to suppress warnings (e.g., "SC1090,SC2148"). Use severity parameter to filter by minimum severity (error, warning, info, style).

Get ShellCheck version and server capability info. Use when: verifying ShellCheck is installed or checking available shell versions. Prefer over: shellcheck when you don't need an actual analysis (cheaper — no script processing). Avoid when: you need script analysis — use shellcheck instead.