The command that displays a manual page for a Linux command is man. Typing “man ls,” for example, opens the locally installed documentation for ls, usually in a terminal pager such as less, where the reader can scroll and search.
Manual pages are organized into numbered sections because the same name can refer to different kinds of material. Section 1 usually covers user commands, while other sections document system calls, library functions, device interfaces, configuration files, and kernel or system conventions. A section can be selected explicitly, such as “man 2 open” for the open system call.
Despite the name “manual page,” the documentation is normally stored on the computer and does not require an Internet connection. The man command formats the source material for terminal display, traditionally using nroff and related macro packages. info can provide more extensive, hyperlinked GNU documentation, while help commonly describes shell built-ins. “which” instead helps locate an executable in the command search path.