Even though "ls -l" displays a file's permissions as "-rw-r--r--", you can't
use "-rw-r--r--" in a chmod command. This is probably one of the most obvious
but overlooked UI inconsistencies in Unix that nobody has fixed after all these
years. Instead we force people to learn octal and type 0644. Meanwhile every
book on Unix/Linux spends pages explaining octal just for this purpose. Time
would have been better spent contributing a patch to chmod.

	-- http://everythingsysadmin.com/2011/02/random-technical-tips-thoughts.html