Get Command help

Obtain Command help-general Linux technology-Linux technology and application information. For more information, see. Bash is the default Shell command used in the system. The help command can provide help information for all Shell commands in Bash.
(1) help Command ?? Can only be used for internal commands
1. display the Bash command list
When you run the help Command separately, the list of Shell commands included in Bash is displayed.
$ Help | head
2. Obtain the help information of the Bash command.
$ Help pwd
3. Only display command format information
When the help and-s options are used together, only the command format information is displayed, without the detailed explanation information.
$ Help-s pwd
(2) "-- help" Command Options
In linux, many external commands provide the "-- help" option. When the command is used with the "-- help" option, only the help overview information of the command is displayed, rather than other operations.
$ Touch -- help
(3) Use the man command to read the manual page
The help on the manual page is a common form of querying Command help information in linux. shell commands and non-shell commands usually provide help information on the manual page.
$ Man ls
Use the Q key to exit the reading environment on the manual page
(4). info command
Use the info command to read the information page
$ Info ls