Permissions

There are three sorts of permissions:

• Read (r)
• Write (w)
• Execute (x)

And each file has permissions defined for three types of users:

• the user (owner) of the file,
• the group of the file,
• other users.

They appear as follows in colums 2 to 10 of the output of ls -l. The letter is replaced by a hyphen (-) where the permission is not set.