🔸 ShellCheck – finds bugs in your shell scripts.
🔸 explainshell – get interactive help texts for shell commands.
🔸 CodeSandbox – online code editor for web application development.
🔸 PHP Sandbox – test your PHP code with this code tester.
🔸 Repl.it – an instant IDE to learn, build, collaborate, and host all in one place.
🔸 vclFiddle – is an online tool for experimenting with the Varnish Cache VCL.