Help command
man: get help
syntax: man [command] or configuration file
Example: man ls (ls command to view the help information)
man services (see the help of the configuration file services)
can be used / to search
whatis: View only command
apropos: View only profile information
syntax: apropos [profile] (can not add absolute path)
example: apropos inittab
--help: command options to see only
syntax Syntax --help
info: the man is similar supports some jumps
help: shell builtin obtaining help information (shell builtin find the path, for example: cd)
Example: help umask
User management commands
useradd: Add a new user
Syntax: useradd [username]
Example: useradd hanzhiyu (add a new user name of the user hanzhiyu)
passwd: Set user password
syntax: passwd [user name]
Example: passwd hanzhiyu (add a password for the user hanzhiyu)
who: View user login information
tty: local terminal pts: remote terminal
w: View user's login details
uptime: view the running time, number of users, load