Shell Checker — Free Online

A general-purpose shell checker for Bash and POSIX sh scripts. Paste and get a structured audit — line-anchored findings, severity grades, exportable report.

The shell checker handles both

#!/bin/bash    # → Bash-friendly rules applied
#!/bin/sh      # → POSIX-only rules, bashisms flagged

What the shell checker covers

Syntax, quoting, error handling, security (injection, unsafe eval, curl-pipe-shell), portability (bashisms under #!/bin/sh), performance (useless-cat, unnecessary subshells), and 7 more dimensions.

Bash-aware, POSIX-aware

The shebang controls strictness. Bash scripts get Bash rules. POSIX sh scripts get POSIX rules plus bashism detection. No manual configuration needed.

For the whole team

Every finding is exportable as Markdown, PDF, or JSON. Great for PR reviews, sign-off documents, and CI dashboards.

Frequently asked questions

Does the shell checker work for zsh?
It targets Bash and POSIX sh. Most zsh scripts share enough syntax to get useful findings, but zsh-specific constructs may false-positive.
Is it a replacement for ShellCheck?
It covers overlapping ground with an AI-assisted layer. Best used alongside ShellCheck in CI.
Is it truly free?
Yes — free for interactive use, no signup, no usage caps for typical workflows.