The three main types of permissions are:Read(r),write(w) and execute(x).
Every file/directory in Linux has three sets of permissions: one for the owner, one for the group, and one for everyone else.
Read permission (r) allows a user to view the contents of a file or directory
Write permission (w) allows a user to modify the contents of a file or create/delete/rename files in a directory
Execute permission (x) allows a user to run a file /directory.
Permissions can be set using either symbolic notation (u+rwx) or numeric notation (775)
The chmod command is used to change file permissions in Linux
The chown command is used to change the owner of a file or directory.