Replace default date and time format in cinnamon-screensaver

patch-cinnamon-screensaver.py

import sys


source = "/usr/bin/cinnamon-screensaver"
time_format = "%l:%M %p"
date_format = "%A, %B %e"
nul = "\x00"


def patch(data, orig, new):
    assert len(orig) >= len(new), repr(new) + " too long"
    o, l = data.find(orig), len(orig)
    assert o >= 0, repr(orig) + " not found"
    return data[:o] + new.ljust(l, nul) + data[o + l:]


new_time_format = sys.argv[1] if len(sys.argv) >= 2 else "%T"
new_date_format = sys.argv[2] if len(sys.argv) >= 3 else "%c"
dest = sys.argv[3] if len(sys.argv) >= 4 else "cinnamon-screensaver"

with open(source, "rb") as fp:
    data = fp.read()

data = patch(data, time_format, new_time_format)
data = patch(data, date_format, new_date_format)

with open(dest, "wb") as fp:
    fp.write(data)