The same series of permissions may be used for directories but they have a slightly different behaviour.
r - you have the ability to read the contents of the directory (ie do an ls) w - you have the ability to write into the directory (ie create files and directories) x - you have the ability to enter that directory (ie cd)
ls testdir (list testdir contents) file1 file2 file3 chmod 400 testdir (400 is 100000000) so r--- --- --- cd testdir (change directory to testdir) -bash: cd: testdir: Permission denied
chmod 100 stops access to a directory
chmod 100 testdir - (100 = 001000000 or --x --- --- so execute rights only) ls testdir ls: cannot open directory testdir: Permission denied cd testdir - I can't list the director, but I can change to it cat file1 - and I can view a file I know exists! this is a test file you have opened it
I am sure I'll find a use for that? :)