[Add to favorites] common Linux commands

Common Linux commands

Command	Explanation	Usage	Example
Ls	Display the contents of a directory (Files And Directories)	Usage: ls or ls directory If LS is left blank, the contents in the face-to-face directory are displayed. You can add the directory path to be viewed after ls.	Ls Ls/ Ls/home/ Ls/etc/sysconf
Ls-l	Detailed display	Usage: ls-l or LS-l directory Note: L is a letter, not a number 1.	Ls-l Ls-L/home
Ls-	Show all files	Usage: ls-A or LS-a directory The file starting with "." is a hidden file, which is also displayed. Otherwise, it is not displayed.	Ls- Ls-La/etc/
CP	Copy a file	Usage: CP source file target file Note: you can add a path name to the file.	CP/home/lion/test1/home/lion/test/Test2
CP-R	Copy the entire directory	Usage: target directory of the original CP-r directory Note: All files in the directory will be copied.	CP/home/lion/mjli/home/lion/test/mjli2
MV	Move a file or directory	Similar to CP, but the original file or directory does not exist after moving. Note: The-R parameter is not used to move a directory.	MV/home/lion/test1/home/lion/Test2 MV/home/lion/mjli/home/lion/mjli2
Touch	Create a file	Usage: Touch file name	Touch/home/lion/test1
Mkdir	Create directory	Usage: mkdir directory name	Touch/home/lion/mjli
Rm	Delete an object	Usage: RM file name	Rm/home/lion/test1
Rm-R	Delete directory	Usage: Rm-r directory name	Rm-r/home/lion/mjli2
Rmdir	Delete an empty directory	Usage: rmdir directory name Note: This directory must be empty; otherwise, it cannot be deleted.	Rmdir/home/lion/mjli2
CD	Change directory path	Usage: CD directory name	CD/etc CD/home/lion
CD ..	To the directory on the previous Layer	Usage: CD ..	CD ..
CD/	To the root directory	Usage: CD/	CD/
PWD	Display the current directory path	Usage: pwd	PWD
Cat	View File Content	Usage: CAT file name	CAT/home/lion/test1
More	View files with long Content	Usage: more file name Note: More can be used with other commands, such as LS-L | more Note: In the display, Press the Space key to scroll one page, press the Enter key to scroll one line, and press the Q key to exit	Ls-L | more More/home/lion/Test2
Less	View files with long Content	Similar to more. In the display, Press Y to scroll up a row	Less/home/lion/Test2
PS aux	View System Processes	Note: It is best to use the aux parameter together.	PS aux
Kill-9	Kill Process	Usage: Kill-9 PID Note: PID (process ID) can be obtained by the PS aux command	Kill-9 1231
W	Show online user information	Usage: W Note: It is more detailed than the WHO command.	W Who
Top	Displays System Task information, including CPU and memory.	Usage: Top	Top
Mesg	Whether to accept write information from others	Usage: mesg y or mesg n Note: accept is Y, and N is not accept.	Mesg y Mesg n
Write	Send information to other users	Usage: write user or write user TTY. Note: tty is used for multiple identical users, which can be obtained by W command.	Write lion Write lion pts/2
Passwd	Change Password	Usage: passwd Note: A super user can change the password of another user, which is a passwd user.	Passwd
Du	Displays the disk usage of each file in the directory (including files in subdirectories)	Usage: du directory name NOTE: If no directory name exists, the current directory is used.	Du DU/home/lion
Du-S	Displays the size of all files in the directory.	Usage: Du-s directory name NOTE: If no directory name exists, the current directory is used.	Du-S Du-S/home/lion
Date	Display System Date and Time	Usage: Date	Date
Uptime	Display System running time	Usage: uptime	Uptime
Clear	Clear current screen	Usage: Clear	Clear
WC	Statistics file, indicating the number of lines, characters, and characters of the file	Usage: WC file name	WC/home/lion/test1
Grep	Filter text	Used with other commands, such Ls | grep sring indicates that only the rows with strings are displayed. Cat file name | grep string indicates that only the rows with strings in the file are displayed.	Ls-L | grep string CAT/home/lion | grep hehe PS aux | grep test1
Grep-n	Filter the text and add the row number before the row.	The user is similar to grep. Just add the parameter.	Ls-L | grep-N string PS aux | grep-N test1
Grep-V	Filters text and lists rows that do not contain a given string.	The user is similar to grep. Just add the parameter.	Ls-L | grep-V string PS aux | grep-V test1
Grep string-R	Search Text	Usage: grep string-r directory name Search for lines containing strings in all objects in the given directory Note: You can also add the-n-V parameter.	Grep string-r/ Grep hehe-r/home/lion
DF	View system hard disk Information	Usage: DF	DF
Free	View system memory information	Usage: free	Free
Ping	Check whether it is connected to the other machine	Usage: ping the IP address or domain name	Ping bbs.ustc.edu.cn Ping 202.38.64.1
Ifconfig	View System Nic Information	Usage: ifconfig Note: common users use/sbin/ifconfig	Ifconfig Ifconfig | more
Route	View System route information	Usage: Route Note: common users use/sbin/route	Route
Echo	Response content	Usage: Echo string Note: The result is string.	Echo hello Echo hehe
Whoami	Displays the username currently in operation	Usage: whoami	Whoami
Exit	Log out of the system	Usage: Exit	Exit
Chmod	See the following description.
CTRL + c	Abort Program Execution	Usage: Ctrl + c	CTRL + c
CTRL + d	Exit System	Usage: Ctrl + d	CTRL + d
Halt	Disable computer	Usage: Halt	Halt
Reboot	Restart the computer	Usage: reboot	Reboot

 

Chmod is used to change the File Permission. In Linux, a file can be read (r) writable (w) executable (x) in three modes, respectively for the owner of the file (onwer), group, and others (other ). If a file is changed to the executable mode, the system regards it as an executable file, and the executable mode of a directory indicates that the user has the right to enter the directory. Chmod is used to change the mode of some files. Its usage is as follows:

Chmod [-R] mode file name

-R: change all subdirectories and files to the mode you want to change.

The mode can be represented by numbers or letters, respectively, as follows:

(1) Number

A three-digit number is given in the order of owner, same-group, and others. R is 4, W is 2, and X is 1, for example, the first digit 7 in 765 indicates that the owner has the R + W + x permission (7 = 4 + 2 + 1 ), the second number 6 indicates that the same group has the R + W permission (6 = 4 + 2 ), the third digit 5 indicates that the other person has the R + x permission (5 = R + x ).

Usage: chmod 765 file name

You can change the number to the required permissions.

(2) Letters

Usage: chmod [Ugo] +/-[rwx] File Name

Example: chmod U + R/home/lion/test1 chmod ug + Rx/home/lion/mjli/hello.com

[] Can appear at the same time, with the following meanings:

+ Or-	R	W	X
U	U + R, u-r indicates that the owner has or cancels the read permission	U + W, U-W indicates that the owner owns or cancels the write permission	U + x, u-X indicates that the owner owns or cancels the executable permission.
G	G + R. G-r indicates that the same group owner has or cancels the read permission.	G + W, G-W indicates that the same group owner or cancelling write permission	G + X, G-X indicates that the same group owner has or cancels the executable permission.
O	O + R and o-r indicate that others have or cancel the read permission.	O + W and o-w indicate that others have or cancel the write permission.	O + X and o-x indicate that others have or cancel executable permissions.

 

Other common features:

	Explanation
>	The output is redirected from the screen to the file, and the original content of the file is cleared.	Usage: Command> file name Note: The command can be the above command, and the file name can have a directory path	Ls-L>/home/lion/lsresult
>	The output is redirected from the screen to the end of the file, and the original content of the file is retained.	Similar to>, but the content of the original file is retained.	Ls-L>/home/lion/lsresult
<	Input redirection. The file content replaces the keyboard input.	Usage: Command <file name Note: The command can be the above command, and the file name can have a directory path	WC
|	Connect two commands (the result of the previous command serves as the input of the next command)	Usage: Command | command	Ls-L | more Ls | grep hello Ls | WC
.	Current Directory	Usage:./file or directory	Ls ./ CP/home/lion/mjli./test/
..	Previous directory	Usage: ../file or directory	CD .. CP ../test1./home/lion/
&	Command as a background command	User: Command &	Gw03 Test &

Edit file VI command usage

Mode Conversion:

 

Commands in command mode:

Command	Explanation	Command	Explanation
	Save and exit	A	Add after current location
: WQ	Save and exit	I	Insert before current position
: W	Save files	O	Create a new row under the current row
: Q	Exit	O	Create a new row above the current row
: Q!	Exit Without saving the disk	Number g	Jump to the number line (skip to the end of the file if no number exists)
: Set number	Display the number of rows at the beginning of each line	Digit YY	How many rows to copy (when no number exists, copy the cursor row)
H	Move cursor left	Number dd	Number of rows to be deleted (delete the cursor row if no number exists)
J	Move cursor down	P	Paste it under the current row
K	Move cursor up	U	Undo the last command operation (multiple operations can be undone)
L	Move cursor right	D	Delete from the cursor to the end of the row
0	Move the cursor to the beginning of the line	X	Delete current character
$	Move the cursor to the end of the row	X	Delete the previous character