the numeric chomd's are grt for speedy typing, but kinda hard to remeber sometimes. there is an alternate way of setting rights, literal.
for example if you whant exec, read and write group meneber read and other nada you would do "chmod u=rwx,g=r mycoolscript.sh"
Specing "who"
u = user
g = group
o = other
a = all (same as ugo)
Specing "what"
r = read
w = write
x = exec
the "who" part can be combined just like the "what" part. ex:
"chmod ug=rw,o=r"
some examples
chmod 777 is chmod a=rwx
chmod 700 is chmod u=rwx
chmod 744 is chmod u=rwx,go=r