Shellcheck

Shellcheck is a static analysis tool for shell scripts. It helps developers identify and fix common errors, syntax issues, and stylistic problems in their scripts, ensuring better code quality and reliability.

What is Shellcheck?

Shellcheck analyzes your shell scripts (bash, sh, ksh) without executing them. It checks for a wide range of potential issues, from simple syntax errors to more complex logical flaws and deviations from best practices. By integrating Shellcheck into your development workflow, you can catch bugs early and write more robust shell scripts.

Key Features and Usage

Shellcheck provides clear and actionable feedback on your scripts. Here are some common ways to use it:

Basic Script Check

To check a shell script named file.sh, use the following command:

shellcheck file.sh

Specifying Shell Type

You can override the script's shebang (e.g., #!/bin/sh) and specify the shell type to check against:

shellcheck --shell sh|bash|ksh file.sh

Ignoring Specific Errors

If you encounter an error that you intentionally want to ignore, you can use the --exclude option. For example, to ignore error code SC1009:

shellcheck --exclude SC1009 file.sh

Ignoring Multiple Errors

You can exclude multiple error codes by separating them with commas:

shellcheck --exclude SC1009,SC1073 file.sh

Disabling Checks within Code

For specific lines or blocks of code, you can add a comment to disable certain checks. For instance, to disable check SC2034 for a particular statement:

# shellcheck disable=SC2034

Benefits of Using Shellcheck

Early Bug Detection: Catches errors before runtime.
Improved Code Quality: Enforces best practices and style guidelines.
Enhanced Script Reliability: Reduces the likelihood of unexpected behavior.
Learning Tool: Helps developers understand common shell scripting pitfalls.

Shellcheck - Static Analysis for Shell Scripts