Help commands (different commands)

The most commonly used help Command help -- helphelp cd to view the built-in command use infoman help cd to view the use of the built-in command to get help: man -- help Baidu google call (friend) Books Forum QQ group communication based on the principle that the problem can be solved in the shortest time, the longer the loss, the greater the loss. -- Help and help can both be used to obtain help information, but there is a significant difference: help: displays simple information about bash shell commands. Using help without any parameters will display all the built-in commands of bash shell. Bash shell built-in Commands include: alias, cd, echo, exit, help, history, pwd, set ...... -- Help: displays a simple command help (most commands can be found, but not all commands ). [Root @ teacher ~] # Passwd -- help view passwd Usage: passwd [OPTION...] <accountName>-k, -- keep-tokens keep non-expired authentication tokens-d, -- delete the password for the named account (root only)-l, -- lock the password for the named account (root only)-u, -- unlock the password for the named account (root only)-e, -- expire the password for the named account (root only)-f, -- force The information provided by force operation help -- help is often too simple and sometimes unable to meet user requirements. Therefore, man must be used) man passwd is the query command by default [usage: man to be queried command] man page is placed in the/usr/share/man/man1 directory and man 5 gets documents online. [usage: man 5 command to be queried] Put man page in the/usr/share/man/man5 directory [root @ teacher doc] # man 1 passwd view description of passwd command [root @ teacher doc] # man 5 passwd view the description of the/etc/passwd file, detailed introduction to [root @ teacher doc] # man 6 passwdNo entry for passwd in section 6 of the manual [root @ tea Cher doc] # man 7 passwdNo entry for passwd in section 7 of the manual [root @ teacher doc] # man 8 passwdNo entry for passwd in section 8 of the manual [root @ teacher doc] # man 9 passwdNo entry for passwd in section 9 of the manual [root @ teacher doc] info provides more complete information than man shows, also updated. Info passwd view info mkdir