Group Discounts available for 3+ students and Corporate Clients

File Permissions

  • Just like every operating system, linux comes with a set of permissions that it uses to protect files, directories and devices on the system.
  • These permissions can be manipulated to allow (or) disallow access to files and directories on different parts of the system.

Basic file permissions:

  • Let’s look at how permissions work first. Linux permissions are implemented through the properties of files and defined by three separate categories.



User:   person who owns the file.

Group:  group that owns the file.

Other:              All other users on the system.

  • Permissions in linux can be assigned one of two ways. You can use the mnemonic or a single digit to represent the permission level.


Operation Digit  Mnemonic  Description
Read r 4 View file contents.
Write w 2 Write to or change.
Execute x 1 Run the file.


Default file permissions:

Umask: Universal mask is a default value that always gets dedicated from maximum  file permission allocated for every file & directory.

  • For super user umask value is # 022.
  • For Normal user umask value is $002

For super user:

  • Maximum permission of a file 666

——————————-Umask  (-)022

  • Default file permission ——>  644
  • Maximum permission of a directory 777

———————————Umask       (-)  022

  • Default directory permission 755
Inclined to build a profession as Linux Developer? Then here is the blog post on Linux Training Online.

For Normal user:

  • Maximum permission of a file —— 666

———————————Umask   (-)_   002


  • Maximum permission of a directory — 777
    umask                —     002
  • To see the umask # umask
  • To change the umask # umask 222
  • To view umask value from the fiel # vim /etc/ bashrc


+        —>      To add a permission.

  •      —>            To remove a permission.

=          —>        To override the permission.

  • Here are some of the commands you can use to work with permissions:

(a) Chmod:- It is used to change the permission of a file and directory. It can be used by the owner of the file (or) by root.

Syn: Chmod [options]            [permission]   [file]

–R —> Acts recursively.

–V —> Provides verbose output.

EX:       1)         # Chmod         u+rw,g+r, o+x   linux

# Chmod         641      linux

2)         #chmod  ugo =rw backup


# chmod          666      backup

3)         #chmod           U-W, g-r, o-x  linux

4)         #chmod           -R         U+W, g+r, o+x linux

5)         #chmod           -R         777 unix

6)         # chmod          755      Unix

(b) Chgrp:

à By using this command we can change group of the file.

Syn:     Chgrp [options] [group name] [file]

-R —> Recursively

-V —> Verbose

Ex:       #ls  -l linux

#chgrp sales linux

(c) Chown:-  This command is used to we can change the owner of the file, as well as  owner & group at a time.

Syn:  Chown [options]           [user:group]    [file]

-R—> Recursively

-V—> Verbose.

EX:       #Chown raju linux                  To Change only owner.

#Chown raju: sales linux       To Change owner & group

#Chown –R ramu: color unix             Recursivly to change.

  • To view the symbolic as well as numeric mode of permission

# stat linux

  • To change the permissions in GUI mode

#navtilus &

  • Assign the permissions in GUI mode:

Right click on file —–> properties —->  permissions.

For indepth understanding of Linux click on

“At TekSlate, we are trying to create high quality tutorials and articles, if you think any information is incorrect or want to add anything to the article, please feel free to get in touch with us at, we will update the article in 24 hours.”

0 Responses on File Permissions"

Leave a Message

Your email address will not be published. Required fields are marked *


Please Enter Your Details and Query.
Three + 6