Syntax:
chmod [OPTIONS] MODE FILE
Permission Values:
Symbolic | Numeric | Meaning |
---|---|---|
r |
4 | Read |
w |
2 | Write |
x |
1 | Execute |
Common Usage:
Mode | Description |
---|---|
755 |
rwxr-xr-x (owner all, others read/exec) |
644 |
rw-r–r– (owner read/write) |
700 |
rwx—— (private) |
Examples:
chmod 755 script.sh
chmod +x file.sh # Add execute permission
chmod -x file.sh # Remove execute
chmod u+x file.sh # Add exec to owner
chmod g-w file.txt # Remove write from group
–
Syntax:
chown [OPTIONS] OWNER[:GROUP] FILE
Options:
Option | Description |
---|---|
-R |
Recursive |
-v |
Verbose output |
Examples:
chown user file.txt
chown user:group file.txt
chown -R newuser /home/newuser/
You must be root or use
sudo
to change ownership.
Syntax:
chgrp [OPTIONS] GROUP FILE
Options:
Option | Description |
---|---|
-R |
Apply recursively |
-v |
Verbose mode |
Examples:
chgrp developers script.sh
chgrp -R teamgroup /var/www/
Useful when multiple users share a group for project files.
Each file or directory in Linux has:
View Ownership:
ls -l
Example output:
-rw-r--r-- 1 alice developers 1024 Jul 3 file.txt
alice
is the ownerdevelopers
is the groupChange Ownership:
chown newuser file.txt
Change Group:
chgrp newgroup file.txt