What does chmod do in Linux?

What does chmod do in Linux?

The chmod command in Linux is used to change the file permissions for users, groups, and others.

Can you explain the permission levels? What do the numbers mean?

Sure! Permissions are represented by three types: read (4), write (2), and execute (1). You combine these for different access.

How would I give read and write permissions to the owner only?

You would use the command chmod 600 filename, which gives read and write permissions to the owner and no permissions to others.

What if I want to give execute permission as well?

You can use chmod 700 filename to give read, write, and execute permissions to the owner.