Getting help: man and --help

The main skill of Part I is not memorizing every command but being able to find the answer quickly in the system itself. The documentation is already on disk.

$ man ls                 # the full manual for a command

Inside man, navigation is like less: arrows scroll, /word searches, q quits. The manual shows every option, the format of the arguments, and examples. When you only need a short reference, most commands have a --help flag:

$ ls --help              # condensed help straight to the terminal

If you do not remember the command name but you know what it does, search by keyword:

$ apropos copy           # commands whose description contains "copy