Table 7.1: Permissions in Linux
+------------------------------------------------------------------------------+
| Code | Name | Allows for Files | Allows for Directories |
|------+---------+--------------------------+----------------------------------|
| r | read | Examine contents of file | List contents of directory |
|------+---------+--------------------------+----------------------------------|
| w | write | Modify file | Add or remove files in directory |
|------+---------+--------------------------+----------------------------------|
| x | execute | Run as a command | Access files in directory |
+------------------------------------------------------------------------------+

Table 7.1 describes the meaning of the read, write, and execute
permissions for both files and directories.

Directory modes can be a little confusing, so here are some examples of
the effects of various combinations:

r-
The user, group, or other with these permissions may list the contents of
the directory, but can do nothing else. The files in the directory can't
be read, changed, deleted, or manipulated in any way. The only permitted
action is reading the directory itself, that is, seeing what files it
contains.

rw-
Write permission has no effect in the absence of execute permission, so
this mode behaves just like the above mode.

r-x