stripping blanks

[micklee74 at hotmail.com]

hi
i have a file test.dat eg

abcdefgh
ijklmn
         <-----newline
opqrs
tuvwxyz
          <---newline

I wish to print the contents of the file such that it appears:
abcdefgh
ijklmn
opqrs
tuvwxyz

here is what i did:
f = open("test.dat")
while 1:
        line = f.readline().rstrip("\n")
        if line == '':
                break
        #if not re.findall(r'^$',line):
        print line

but it always give me first 2 lines, ie
abcdefgh
ijklmn

What can i do to make it print all..?
thanks