Linux chmod Change permission Properties command

Change permission Properties command chmod

chmod (change mode)-change-file access permissions

chmod is a command used to change the permissions of a file or directory, but only the owner and Superuser root of the file have this permission. There are two ways to change the permissions of a file or directory through chmod: One is to set permissions by means of a permission letter and an operator expression, and the other is to use numbers to set permissions.

There are two ways to change permissions: 1. Digital notation (commonly used) 2. Character notation

Digital permission notation:

chmod [Numeric combination] File name

R 4

W 2

X 1

-0

Character-type permission notation:

chmod [user Type] [+|-|=] [permission character] file name

chmod	User type	Manipulating characters	Permission characters	file or directory
	U (user)	+ (Join)	R
	G (Group)
	O (Others)	-(minus)	W
	A (All)	= (set)	X

User or user group definition:

U represents a master user

G Representative Group

O on behalf of other users

A represents the owner, the group, and other users, which is all of the three users (or groups) above

Permission Definition Letter:

R stands for Read permission

W Stands for write permission

X represents Execute Permissions

Permissions increment or decrement characters:

+ Add a permission

-Cancel a permission

= Cancel all other permissions to give given permission

Command parameters:

-C: If the file permission has changed, it will not show its change action

-F: Do not display an error message if the file permissions cannot be changed

-V: Show details of permission changes

-r: The same permissions change for all files in the current directory as subdirectories (that is, they are changed in a recursive manner)

--HELP: Show Auxiliary Instructions

--version: Display version

Examples of use of digital permissions:

Such as:

[Email protected] zdw]# ls-l 2.txt-rw-r--r--. 1 root root Notoginseng 14:30 2.txt

Owner: Root rw-=4+2+0=6

User group: Root r-x=4+0+0=4

Others: r--=4+0+0=4

The permission for the 2.txt file is 644

Change the 2.txt permission to-r-xrwxr-x

[Email protected] zdw]# chmod 575 2.txt[[email protected] zdw]# ls-l 2.txt-r-xrwxr-x. 1 root root Notoginseng 14:30 2.txt

Change permissions for files in ZDW folders and folders

[[Email protected] zdw]# ll zdwtotal 0-rw-r--r--.  1 root root 0  apr 28 09:56 e-rw-r--r--.  1 root root 0 apr 28 09:56  i-rw-r--r--.  1 root root 0 apr 28 09:56 q-rw-r--r--.  1  root root 0 apr 28 09:56 r-rw-r--r--.  1 root root 0  apr 28 09:56 t-rw-r--r--.  1 root root 0 apr 28 09:56  u-rw-r--r--.  1 root root 0 apr 28 09:56 w-rw-r--r--.  1  root root 0 Apr 28 09:56 y[[email protected] zdw]# ll  zdw -lddrwxr-xr-x. 2 root root 4096 apr 28 09:56 zdw[[email  protected] zdw]# chmod -r 755 zdw                        #使用-R assigns files to folders and folders [[email protected] zdw]#  ll zdwtotal 0-rwxr-xr-x. 1 root root 0 apr 28 09:56  E-rwxr-xr-x. 1 root root 0 apr 28 09:56 i-rwxr-xr-x. 1 root  root 0 apr 28 09:56 q-rwxr-xr-x. 1 root root 0 apr  28 09:56 r-rwxr-xr-x. 1 root root 0 Apr 28 09:56  T-rwxr-xr-x. 1 root root 0 apr 28 09:56 u-rwxr-xr-x. 1 root  root 0 apr 28 09:56 w-rwxr-xr-x. 1 root root 0 apr  28 09:56 y

Example of using character permissions:

Permission to add X to a user

[Email protected] zdw]# ls-l 1.txt-rw-r--r--. 1 Root bin 151 Apr 15:46 1.txt[[email protected] zdw]# chmod u+x 1.txt #u表示对前三位处理 + permissions on x [[email P Rotected] zdw]# ls-l 1.txt-rwxr--r--. 1 Root bin 151 Apr 15:46 1.txt #已加上x的权限

Empowering User Groups

[Email protected] zdw]# chmod g=rx 1.txt #给用户组rx的权限 [[email protected] zdw]# ls-l 1.txt-rwxr-x R--. 1 Root bin 151 Apr 15:46 1.txt

Also give permission:

[[email protected] zdw]# chmod u=wx,g=rwx,o=w 1.txt               #用, number separated, can be simultaneously empowered [[Email protected] zdw]# ls -l  1.txt               -- Wxrwx-w-. 1 root bin 151 apr 27 15:46 1.txt[[email protected]  zdw]# chmod ugo-w 1.txt                        #用-minus w privileges at the same time [[EMAIL PROTECTED] ZDW] # ls -l 1.txt      ---xr-x---.  1 root bin 151  Apr 27 15:46 1.txt[[email protected] zdw]# chmod a-x 1.txt                         &nbSP; #ugo相当于a, minus x permission [[email protected] zdw]# ls -l 1.txt    ---- R-----.  1 root bin 151 Apr 27 15:46 1.txt[[email protected]  zdw]# chmod +x 1.txt                           #什么都不填直接写 + number, also equivalent to all [[email  protected] zdw]# ls -l 1.txt   ---xr-x--x. 1 root bin  151 apr 27 15:46 1.txt

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Linux chmod Change permission Properties command