Summary of the basic help query command under Linux system

Time:2021-6-18

Command name – help | more

Displays a brief command help (valid for most commands). For example, try “CP – help | more.”– The functions of “help” and “H” switch in DOS are similar. When the output exceeds one screen, it is necessary to add “more”.

Man command
Display the help manual of the corresponding command system. Enter “Q” to exit the browser. If you set advanced options, try typing “man”. The command “info command name” is similar to the command “man command name” in function, but contains more up-to-date information. Helpbooks can be a little hard for beginners to read – they were originally written for UNIX programmers. Using “command name – help” can get a simple and easy to digest command help. Some programs come with readme files or other help information files. It is recommended that you look at the directory / usr / share / doc. To display the command help in the specified part, you can use the command “Man 3 exit”, which only displays the “third part” of the exit command help manual; Or use the command “man – a exit”, which displays “all parts” of the exit command help manual. All parts of the exit command help are: 1 – user command; 2 – system call; 3 – sub call; 4 – equipment; 5 – file format; 6 – Games; 7 – miscellaneous; 8 – system management; 9 – new content. To print the complete command help, you can use the command “man command name | col – B | LPR” (optional col – B to delete all backspace keys and some special characters that are difficult to read).
Because most programs have their own manuals, you can get help with the man command. After execution, press Q on the man page to exit.

Get help from LS

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The code is as follows:

$ man ls

See how many manuals with the same name (for different aspects)

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The code is as follows:

$ man -f ls
ls (1) – list directory contents
ls (1p) – list directory contents

View specific manuals

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The code is as follows:

$ man 1p ls

Info command name

Displays help for the specified command. The info command is an advantage of replacing the man command. It usually carries the latest system information. Use the “space bar” and “backspace bar” more, or you may be confused. Press “Q” to exit. If you don’t think it’s easy to use the method for browsing – you can also try using the pInfo command to see if you would prefer this alternative.

Different from man, it can jump in each node just like browsing a web page.

Browse from the first page of the document

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The code is as follows:

$ info

Get help with specific programs

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The code is as follows:

$ info program

Apropos command name

Give a help list for the command name you enter.

Whatis command name

Gives a short list that matches the name of the command entered. The whatis command is a bit like apropos – they use the same database. The difference is that whatis searches for keywords and apropos searches for specific descriptions of keywords.

Help command name

Displays simple information about bash shell built-in commands. Using the help command with no arguments displays all the built-in commands of the bash shell. The shortest bash shell built-in commands should include: alias, BG, CD, echo, exit, export, help, history, jobs, kill, logout, PWD, set, source, ulimit, umask, unalias, unset

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The code is as follows:

$man — help get man’s help
$info — help get help from info
$LS — help get help from LS

kdehelp

kdehelpcenter

Use the command that works on your system. Use a graphical browser to display the help of the whole system. Generally speaking, KDE help is realized by putting the corresponding icon on the KDE control board. Peer to peer Gnome help systems can use the Gnome help browser command.