Use this command to change file or directory attributes. If you do
ls -l in the present working directory, you would see file attributes for your files and directories in the present working directory. To change the permissions you can use “chmod”.
chmod XXX <file-name> or chmod XXX <directory-name>
Each ‘X’ denotes a value for:
Values for X
‘X’ above can be assigned value from 0-7.
X=4: for read only. X=2: for write only. X=1: for execute only.
You can get a combination of permisssions eg. “read and write” by givng ‘X’ a combined value as ‘X=6’ (‘X=6’ is obtained by adding read and write value).
// read, write and execute permission X:4+2+1=7 // read and write permission X:4+2=6 // read only permission X:4
Say you want to assign permission for a certain file or directory as:
- User: Read and Write and Execute
- Group: Read and Write
- Others: Read Only
Then you can run the
chmod as follows:
chmod 764 file.txt chmod 764 test_dir
To change group attribute of a file or directory. Each user belongs to a group. If you need to change the group the user belongs to use this command.
chgrp <group-name> <file-name> or chgrp <group-name> <directory-name>
For example, if you have file a file “file.txt” and directory “test_dir”, and you want to assign a group “admin” to it, you can do that by:
chgrp admin file.txt chgrp admin test_dir
To change owner of a file or directory. It can also be used to change the file group along with the user.
chown <owner-name> <file-name> or chwon <owner-name> <directory-name>
Lets assume you have file a file “file.txt” and directory “test_dir”, and you want to assign a owner as “minto” to it, you can do that by:
chown jsbisht file.txt chown jsbisht test_dir
If you want to change user and group simultaneously:
chown <owner-name>:<group-name> <file-name> or chown <owner-name>:<group-name> <directory-name>
chown jsbisht:admin file.txt chown jsbisht:admin test