README

ShellCheck - A shell script static analysis tool

ShellCheck is a GPLv3 tool that gives warnings and suggestions for bash/sh shell scripts:

!Screenshot of a terminal showing problematic shell script lines highlighted

The goals of ShellCheck are

 To point out and clarify typical beginner's syntax issues that cause a shell
  to give cryptic error messages.

 To point out and clarify typical intermediate level semantic problems that
  cause a shell to behave strangely and counter-intuitively.

 To point out subtle caveats, corner cases and pitfalls that may cause an
  advanced user's otherwise working script to fail under future circumstances.

See the gallery of bad code for examples of what ShellCheck can help you identify!

 Table of Contents

 How to use
   On the web
   From your terminal
   In your editor
   In your build or test suites
 Installing
 Compiling from source
   Installing Cabal
   Compiling ShellCheck
   Running tests
 Gallery of bad code
   Quoting
   Conditionals
   Frequently misused commands
   Common beginner's mistakes
   Style
   Data and typing errors
   Robustness
   Portability
   Miscellaneous
 Testimonials
 Ignoring issues
 Reporting bugs
 Contributing
 Copyright
 Other Resources

 How to use

There are a number of ways to use ShellCheck!

 On the web

Paste a shell script on  for instant feedback.

ShellCheck.net is always synchronized to the latest git commit, and is the easiest way to give ShellCheck a go. Tell your friends!

 From your terminal

Run shellcheck yourscript in your terminal for instant output, as seen above.

 In your editor

You can see ShellCheck suggestions directly in a variety of editors.

 Vim, through ALE, Neomake, or Syntastic:

!Screenshot of Vim showing inlined shellcheck feedback.

 Emacs, through Flycheck or Flymake:

!Screenshot of emacs showing inlined shellcheck feedback.

 Sublime, through SublimeLinter.

 Pulsar Edit (former Atom), through linter-shellcheck-pulsar.

 VSCode, through vscode-shellcheck.

 Most other editors, through GCC error compatibility.

 In your build or test suites

While ShellCheck is mostly intended for interactive use, it can easily be added to builds or test suites.
It makes canonical use of exit codes, so you can just add a shellcheck command as part of the process.

For example, in a Makefile:

Makefile
check-scripts:
     Fail if any of these files have warnings
    shellcheck myscripts/.sh


or in a Travis CI .travis.yml file:

yaml
script:
   Fail if any of these files have warnings
  - shellcheck myscripts/.sh


Services and platforms that have ShellCheck pre-installed and ready to use:

 Travis CI
 Codacy
 Code Climate
 Code Factor
 Codety via the Codety Scanner
 CircleCI via the ShellCheck Orb
 Github (only Linux)
 Trunk Code Quality (universal linter; allows you to explicitly version your shellcheck install) via the shellcheck plugin
 CodeRabbit

Most other services, including GitLab, let you install
ShellCheck yourself, either through the system's

Top issues

Latest release

This release is dedicated to Satisfactory, even though my giant
3D ball of rat's nest conveyor belt spaghetti is anything but.

  CHANGELOG

   v0.11.0 - 2025-08-03
   Added
  - SC2327/SC2328: Warn about capturing the output of redirected commands.
  - SC2329: Warn when (non-escaping) functions are never invoked.
  - SC2330: Warn about unsupported glob matches with [[ .. ]] in BusyBox.
  - SC2331: Suggest using standard -e instead of unary -a in tests.
  - SC2332: Warn about [ ! -o opt ] being unconditionally true in Bash.
  - SC3062: Warn about bashism [ -o opt ].
  - Optional av