chmod Linux Command Cheatsheet

1991




chmod stands for "change mode". It is used to change the permissions to files/ directories

Syntax

chmod [options] <permissions> <file_name> 

Options

OptionDescription
-Rchange permissions for files and directories recursively
-vVerbose(this display all the files that the command is processing)
-cChange (this will display only the files it is changing the permission for)
-fsilent mode (this will supress errors)
-hthis change the permission of the symbolic link instead of the main file

Example

chmod 777 foo.txt

Permissions

Following are the four possible digits and their respective permissions

DigitPermission
4read
2write
1execute
0no permission

Users can also sumup these digits and can use like following

Derived DigitsPermission
74+2+1 = read + write + execute
64+2 = read + write
54+1 = read + execute
32+1 = write + execute

Permissions for user, group, others

Owner of the file can set different permissions for user, group & others

Example

chmod u=rwx,g=rx,o=r foo.sh # this is same as chmod 754 foo.sh
u = user
g = group
o = others

r = read
w = write
x = execute