Linux File Permissions

d	                 r	w	x	           r	w	x	             r	w	x
 	                  Owner	           Group	              Other
Directory	Read	Write	Execute	Read	Write	Execute	Read	Write	Execute

  (R)	(W)	(X)
0	No	No	No
1	No	No	Yes
2	No	Yes	No
3	No	Yes	Yes
4	Yes	No	No
5	Yes	No	Yes
6	Yes	Yes	No
7	Yes	Yes	Yes

777 is the same as rwxrwxrwx

755 is the same as rwxr-xr-x

666 is the same as rw-rw-rw-

744 is the same as rwxr--r--

chmod nnn filename