Most commands have built-in help info, usually with the
-h option, e.g.
$ ls --help will give you more info about the command
Or open the manual by calling
$ man ls will show the manual page of
Notice that at the very beginning of the manual, the command often has a number associated with it, like
LS(1), the number is the section of the manual:
- Section 1: user commands
- Section 2: system calls
- Section 3: library functions
- Section 4: special files
- Section 5: file formats
- Section 6: games
- Section 7: conventions and miscellany
- Section 8: administration and privileged commands
- Section L: math library functions
- Section N: tcl functions
This info can be found in the manual of manual:
$ man man.
The same entry may appear in different sections, e.g. to check manual for
mount in system calls vs admin command:
$ man 2 mount # the system call $ man 8 mount # the admin command
man -k to search the man pages, e.g.
$ man -k mount will not only return
mount but also
cgroupfs-mount, etc. This is equivalent to
man -f to list all sections that have the term.
$ man -f mount mount (8) - mount a filesystem mount (2) - mount filesystem