Help in Linux: --help and man

--help prints a brief usage summary, while man opens the full manual.

Common cases

mkdir --help     # a short reference in the terminal
man ls           # the full manual, q to quit
man 5 passwd     # section 5: a file format, not a command
apropos network  # search man pages by keyword

How it works: man sections

The man manuals are split into numbered sections: 1 for user commands, 5 for file formats, 8 for admin commands. So man 5 passwd describes the /etc/passwd file format, while man 1 passwd is the password-changing command. --help is built into the program itself and always at hand, while man lives as separate files on the system. The real skill is not memorising flags but finding them here quickly.

Used in

You need this in the lesson Getting help. The theory is the chapter Getting help: man and --help.

See also

which, type, whereis.

Try it

Open the sandbox: a real throwaway Linux terminal in your browser. Run the commands above by hand - the container is deleted when you leave.