perform rot0 -- rot25

gistfile1.txt

$ echo -n 'hello world' | python rot.py
hello world
ifmmp xpsme
jgnnq yqtnf
khoor zruog
lipps asvph
mjqqt btwqi
nkrru cuxrj
olssv dvysk
pmttw ewztl
qnuux fxaum
rovvy gybvn
spwwz hzcwo
tqxxa iadxp
uryyb jbeyq
vszzc kcfzr
wtaad ldgas
xubbe mehbt
yvccf nficu
zwddg ogjdv
axeeh phkew
byffi qilfx
czggj rjmgy
dahhk sknhz
ebiil tloia
fcjjm umpjb
gdkkn vnqkc

rot.py

import sys

def rot(s, n):
    s = bytearray(s)
    for i, c in enumerate(s):
        if 0x41 <= c <= 0x5a:
            s[i] = ((c-0x41+n) % 0x1a) + 0x41
        elif 0x61 <= c <= 0x7a:
            s[i] = ((c-0x61+n) % 0x1a) + 0x61
    return s

data = sys.stdin.read()

for n in xrange(26):
    print rot(data, n)