Agent Skills: Bash Quality Gate

Bash Quality Gate

Run a standardized set of shell script quality checks. Auto-fix what's fixable, report the rest with specific locations.

Prerequisites

Verify these tools are available before running checks. Both are installed via Homebrew.

• shfmt — shell formatter (brew install shfmt)
• shellcheck — static analysis (brew install shellcheck)

Check Sequence

Run checks in this order. Formatting first so shellcheck analyzes clean code.

1. Format (auto-fix)

Run shfmt -w -i 2 -ci -bn . on all .sh files — report which files were modified. If no files changed, report "formatting clean."

Flags:

• -i 2 — 2-space indent
• -ci — indent switch cases
• -bn — binary ops start of line

If a project has an .editorconfig, shfmt picks it up automatically — skip the explicit flags.

2. Lint (report)

Run shellcheck -x *.sh **/*.sh — report issues with file, line, rule code, and severity. The -x flag follows source directives.

If scripts lack a shebang, shellcheck defaults to sh. Note any scripts missing shebangs and suggest adding them.

3. Portability (report)

Run shellcheck --shell=sh *.sh **/*.sh — check POSIX compliance. Report bash-specific constructs that would break on sh/dash. Skip this step if all scripts explicitly declare #!/bin/bash or #!/usr/bin/env bash — they've opted into bash.

Output

After all checks complete, present a summary table:

| Check       | Status | Details              |
|-------------|--------|----------------------|
| shfmt       | FIXED  | 2 files formatted    |
| shellcheck  | WARN   | 3 issues (1 error)   |
| portability | SKIP   | All scripts use bash |

Then list specific issues grouped by file, with line numbers and ShellCheck codes (e.g., SC2086). Offer to fix reported issues if the user wants.

File Discovery

• Find scripts by extension: *.sh
• Find scripts by shebang: #!/bin/bash, #!/bin/sh, #!/usr/bin/env bash
• Check the current directory and subdirectories
• Skip node_modules/, .git/, and vendor/ directories