Chmod and Chown Commands

1. Chmod

chmod - means that Change Mode. It is a command that controls the users permission on the file or directory in Linux.
File accessing permissions of Linux/Unix are divided into three levels: file owner(Owner), user group(Group), and other users(Other Users).

file-permissions-rwx

The permission of the file or directory can be changed only by the owner or the superuser, others can’t. There are two types model followed to specify the permissions.
- Octal Model and Symbolic Model

Octal File Permissions Table

Number	Permissions	rwx	Binary
7	Read + Write + Execute	rwx	111
6	Read + Write	rw-	110
5	Read + Execute	r-x	101
4	Read-only	r–	100
3	Write + Execute	-wx	011
2	Write-only	-w-	010
1	Execute-only	–x	001
0	None	—	000

1 2	touch sample.sh ll

Output: -rw-rw-r-- 1 raman raman 0 三 31 14:07 sample.sh. Here, the first character (-) means it is a file.

When you create a file using touch command by default the permissions will be 664(-rw-rw-r–).

Changing the permissions to all(user, group, others).

1 2	chmod -v 777 sample.sh ll

Output: -rwxrwxrwx 1 raman raman 0 三 31 14:11 sample.sh*

1 2	mkdir sample ll

Output: drwxrwxr-x 2 raman raman 4096 三 31 14:26 sample/. Here, the first character (d) means it is a directory.

When you create a file using touch command by default the permissions will be 775(drwxrwxr-x).

For changing permissions multiple files or directories,

1 2	chmod -vR 777 directory_path/* #for directories chmod -vR 777 file_name/* #for files

chown - means that Change Ownership. This command is used to change the owner of the file or the directory.
chown requires the permission of superuser(root) to execute it.
1
2
touch sample.sh
ll
Output: -rw-rw-rw- 1 raman raman 0 三 8 00:35 testfile
Changing the ownership from raman to jenkins.
1
2
sudo chown -v jenkins:jenkins sample.sh
ll
Output: -rw-rw-rw- 1 jenkins jenkins 0 三 8 00:35 testfile

For changing permissions multiple files or directories,

1 2	chown -vR username:usergroup directory_path/* #for directories chmod -vR username:usergroup file_name/* #for files