ShellCheck is a static analysis tool that shows warnings and suggestions concerning bad code in bash/sh shell scripts. It can be used in several ways: from the web by pasting your shell script in an online editor (Ace – a standalone code editor written in JavaScript) in https://www.shellcheck.net (it is always synchronized to the latest git commit, and is the simplest way to give ShellCheck a go) for instant feedback.

Alternatively, you can install it on your machine and run it from the terminal, integrate it with your text editor as well as in your build or test suites.

There are three things ShellCheck does primarily:

• It points out and explains typical beginner’s syntax issues that cause a shell to give cryptic error messages.
• It points out and explains typical intermediate level semantic problems that cause a shell to behave strangely and counter-intuitively.
• It also points out subtle caveats, corner cases and pitfalls that may cause an advanced user’s otherwise working script to fail under future circumstances.

yum install epel-release -y

for amazon linux use the following command:

sudo amazon-linux-extras install epel

install shellcheck

yum install ShellCheck -y

apt-get install shellcheck

dnf install ShellCheck

shellcheck test.sh