Shulou(Shulou.com)06/01 Report--

This article will explain in detail what Linux commands must have. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Common shortcut keys:

① ctrl + c: stop the process

② ctrl+l: clear the screen

③ ctrl + Q: exit

④ is good at using the tab key.

⑤ arrow keys: find commands that have been executed

Common command: "[option]" represents optional or non-optional when executing the command

Pwd: displays the absolute path of the current working directory

Ls: lists the contents of the directory

Syntax: ls [option] [directory or file]

Options:

-a: all files, along with hidden files (beginning with. Listed together (commonly used)

-l: long data string list, including file attributes, permissions and other data; (commonly used)

Scene:

Mkdir: create a new directory

Syntax: mkdir [option] the directory to be created

Option:-p: create a multi-tier directory

Scene:

Rmdir: delete an empty directory

Touch: creating an empty file

Syntax: touch file name

Scene: touch test.java

Cp: copy a file or directory

Syntax:

(1) cp source dest (function description: copy source file to dest)

(2) cp-r sourceFolder targetFolder (function description: recursively copy the entire folder)

Rm: remove files or directories

Syntax:

(1) rmdir deleteEmptyFolder (function description: delete empty directory)

(2) rm-rf deleteFile (function description: recursively delete everything in the directory)

Mv: move files and directories or rename

Syntax:

(1) mv oldFileName newFileName (function description: rename)

(2) mv / temp/movefile / targetFolder (function description: move files)

Cat: viewing file contents

Syntax: cat [option] file name

Options:

-A: the equivalent of-vET's integration option, which lists some special characters instead of white space

-b: list the line number, display the line number only for non-blank lines, and the blank lines are not marked with line numbers!

-E: displays the line break byte $at the end

-n: list the line number, and there will be a line number along with the blank line, which is different from the option of-b

-T: display the [tab] button as ^ I

-v: list some unrecognizable special characters

Scene:

Tac: view the contents of the file, starting with the last line

Syntax: tac file name

Scene:

More: viewing file contents

Syntax: more file name

Feature usage:

Blank key (space): for turning down one page

Enter: stands for turning down "one line"

Q: the representative immediately leaves the more and no longer displays the contents of the file.

Ctrl+F scrolls down one screen

Ctrl+B returns to the previous screen

= output the line number of the current line

: F output file name and line number of the current line

Less: viewing file contents (similar to more function)

Syntax: less file name

Feature usage:

Blank key: turn down one page

[pagedown]: turn a page down

[pageup]: turn a page up

/ string: the function of searching down for "string"; n: looking down; N: looking up

? String: the function of searching for "string" up; n: looking up; N: looking down

Q: leave the less program

Head: view the contents of the file (just the first few lines)

Syntax: head-n line count file

Example: head-n 10 file (description: view the first 10 lines of the file, 10 can be any number of lines)

Tail views the contents of the file

Syntax:

(1) tail-n 10 file (description: view the last 10 lines of the file, 10 is any number of lines)

(2) tail-f file (description: track all updates to the document in real time)

Echo write

Syntax:

(1) the content to be displayed by echo > > the file in which the content is stored (description: the content to be displayed, stored in a file)

(2) echo variable (description: displays the value of the variable)

Scene:

Ln soft link

Syntax:

Ln-s [original file] [target file] (description: create a soft link to the original file, which is stored in the target file directory)

Useradd add a new user

Syntax: useradd user name

Passwd sets user password

Syntax: passwd user name (description: set user password)

Id determines whether the user exists.

Syntax: id user name

Su switching user

Syntax: su user name (description: switch user)

Userdel Delete user

Syntax:

(1) userdel user name (description: delete the user but save the user's home directory)

(2) userdel-r user name (description: user and user home directory, both deleted)

Who to view login user information

Syntax:

(1) whoami (description: show your own user name)

(2) who am i (description: displays the user name of the logged-in user)

(3) who (description: see which users are currently logged on to this machine)

Set john ordinary users to have root permissions

Modify the / etc/sudoers file, find the following line, and add a line under root, as follows:

# # Allow root to run any commands anywhere

Root ALL= (ALL) ALL

John ALL= (ALL) ALL

Cat / etc/passwd to see which groups have been created

Syntax: cat / etc/passwd

Usermod modifies user

Syntax: usermod-g user group username

New group for groupadd

Syntax: groupadd group name

Groupdel delete group

Syntax: groupdel group name

Groupmod revises the group syntax: groupmod-n new group name old group name

Cat / etc/group to see which groups have been created

Syntax: cat / etc/group

Find looks for files or directories

Syntax: find [search scope] [matching criteria]

Scene: find / opt/-name * .txt

Grep searches the file for lines that match the string and outputs

Syntax: grep+ parameter + find content + source file

Parameters:

-c: outputs only the count of matching rows

-I: case-insensitive (for single characters only)

-h: do not display file names when querying multiple files

-l: when querying multiple files, only the file names containing matching characters are output.

-n: displays matching lines and line numbers

-s: does not display error messages that do not exist or have no matching text

-v: displays all lines that do not contain matching text

Scene:

Grep-C 1'1' test.txt

Grep-n 1 test.txt

Chmod: change permissions

Syntax: chmod [{ugoa} {+-=} {rwx}] [file or directory] [mode=421] [file or directory]

Description:

Change file or directory permissions

File: r-view; w-modify; x-execute file

Directory: r-lists directory contents; w-creates and deletes in the directory; x-enters the directory

A prerequisite for deleting a file: the directory in which the file is located has write permission before you can delete the file.

Scene:

[root@hadoop100] # chmod uplix test1.java

[root@hadoop100] # chmod gallex test1.java

[root@hadoop100] # chmod ostatx test1.java

# 777: maximum permissions

[root@hadoop100] # chmod 777 test1.java

[root@hadoop100] # chmod-R 777 testdir

Chown: change the owner

Syntax: chown [end user] [file or directory] (description: change the owner of a file or directory)

Scene:

[root@hadoop106 test1] # chown John test1.java

Chgrp: change the group you belong to

Syntax: chgrp [end user group] [file or directory] (description: change the group to which a file or directory belongs)

Scene:

[root@hadoop100] # chgrp usergroup test1.java

This is the end of this article on "what will be ordered by Linux". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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