Three types of users can access a file: the owner of the file (owner), a member of a group to which the owner belongs (group; see page 959 for more information on groups), and everyone else (other). A user can attempt to access an ordinary file in three ways: by trying to read from, write to, or execute it. Three types of users, each able to access a file in three ways, equal a total of nine possible ways to access an ordinary file.
ls –l: Displays Permissions
When you call ls with the –l option and the name of an ordinary file, ls displays a line of information about the file. The following example displays information for two files. The file letter.0610 contains the text of a letter, and check_spell contains a shell script, ...