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This article is a detailed introduction to "how to use Linux help command". The content is detailed, the steps are clear, and the details are properly handled. I hope this article "how to use Linux help command" can help you solve your doubts. Let's go deeper and learn new knowledge together with the ideas of Xiaobian.

Linux common command help command help command can only display bash built-in command help information, and for external command help information can only be used man or info command.

help This command is a bash built-in command that displays help information for bash built-in commands.

The help command can only display help information for bash built-in commands, while help information for external commands can only be viewed using the man or info commands.

syntax help(option)(parameter) option-d: Displays a brief description of the built-in command. -m: Output help information for built-in commands in the format of a man manual. -s: Output only built-in command formats. When no option is specified: The output help message is similar to the-m option, but lacks the paragraph name and the 'SEE ALSO','IMPLEMENTATION'sections. Parameter bash built-in command (can be multiple, please separate with spaces).

Q: What commands are bash built-in commands? How do I know if a command is bash built-in?

A: You can use 'man builtin' or 'man builtins' in the terminal to get it; you can check the help information of bash built-in command 'type'.

Q: How do I get help information from the help command itself?

A: Pass help as an argument to the help command;)

Q: Why can I use 'man echo' to check help information?

A: Because in addition to bash's built-in echo, GNU/linux's coreutils package also has this command; in echo's man manual, the 'NOTE' in the DESCRIPTION section also indicates that it is different from the built-in with the same name.

PS: When you define a function called 'echo' in a shell script, what is the priority when it is invoked?

Please refer to the 'builtin' command

Q: I need more help with bash.

A: Limited by space and subject, you can execute 'man bash' and 'info bash' on the terminal, visit bash official website, and search engine.

The example uses the help command to display help information for the shell internal shopt command by entering the following command:

help shopt #Get help with shopt command shopt: shopt [-pqsu] [-o long-option] optname [optname...] Toggle the values of variables controlling optional behavior. The -s flag means to enable (set) each OPTNAME; the -u flag unsets each OPTNAME. The -q flag suppresses output; the exit status indicates whether each OPTNAME is set or unset. The -o option restricts the OPTNAMEs to those defined for use with `set -o'. With no options, or with the -p option, a list of all settable options is displayed, with an indication of whether or Not each is set. Read here, this article "Linux help command how to use" article has been introduced, want to master the knowledge of this article also need to practice to understand, if you want to know more about the content of the article, welcome to pay attention to the industry information channel.

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