To add a user called bart:
$ sudo useradd bart
To add a pre-existing user called bart to the group simpsons:
$ groupadd -g simpsons bart
File and directory permissions are set in Linux with pe
chmod is the default UNIX tool for modifying file and directory permissions.
To allow anyone in the same group to read, write or execute files (only files which are currently executable by a user), as well as allow them to read contents of all sub-directories:
$ sudo chmod -R g+rwX my_parent_dir/
To change permissions recursively on a group of files, use:
$ sudo chmod -R <mode flags> my_directory/
Using a capital X instead of a lower-case x results in the executable bit only being set if the file is a directory or the executable bit is already set for some user. This is useful when applying changes to multiple files (using the recursive option -R), as you usually don’t want to make things such as text files executable!