File system permissions explained

From Oxxus Wiki

Permissions on Linux file systems are described with 9 bits. There is a group of 3 bits which describes whether read, write or execute (r, w, x respectfully) are applied to user, group or to all.

When you type the command:

ls -al

You will see in the first column description of permissions applied to the file or directory.

To change the permissions you would use command chmod.

chmod u+rw /home/user/file would make file's respectful user able to read and write to the file. chmod g-x /home/user/file would make the file's group unable to execute the file.

With -R switch permissions are applied to recursively throughout the directory.

To change the ownership of the file you can use chown or chgrp.

chown would change the owner of the file or directory and the format is:

chown [user] [path]

The same goes for the chgrp with group name instead of the user.