ShellCheck - A static analysis tool for shell scripts

ShellCheck is a tool that gives warnings and suggestions for bash / sh shell scripts. It helps to clarify typical beginner's syntax issues that cause a shell to give cryptic error messages. Identifies intermediate level semantic problems that cause a shell to behave strangely and counter-intuitively. It points out corner cases and pitfalls that may cause an advanced user's otherwise working script to fail under future circumstances.