Help and the shell

Articles

• bash — the command shell — A command interpreter for interactive input, builtins, and shell scripts.
• Getting help at the terminal — How to quickly find a command's options: man, --help, apropos and tldr; how to read a man page.
• which / type / whereis — where a command lives — Find out which binary will run, whether it's a builtin or an alias, where it lives, and its man page.
• Glob patterns and brace expansion — Shell substitutions — * ? [] {} — and how they differ from regular expressions.
• Environment variables and PATH — Environment variables: env, export, $PATH, ~/.bashrc and profiles; where "command not found" comes from.
• printf and echo — printing text in scripts — Formatted output in the shell — more reliable than echo, formats and special characters.