When a file is created, it is possible to give permissions by default.
umask display the default permissions.
It returns the permissions that are substracted to a file from an "all permission" value:
a file is
a directory is
xmeans that one can enter the directory for browsing)
For example, if umask is 022 (which corresponds to
-ww), any file will be created with a default
while any directory will be made with
To prevent any user other than the owner to browse a directory or read a file, umask must be set to 077.