In unix each files has certain permissions like read, write and execute. A user can manipulate the permissions of a file using 'chmod' command.
In UNIX, there are three permissions used to grant a certain level of access to a file or folder.
These are slightly changed for directories:
These permissions can be represented using the letters "r" for read, "w" for write, and "x" for execute. They can also be represented numerically: 4 for read, 2 for write and 1 for execute.