nap — better than sleep

nap.py

#!/usr/bin/env python

from sys  import argv, exit
from time import sleep, time

import re

if len(argv) != 2:
    print('Usage: nap <interval>')
    print('Where: <interval> is <num>h hours')
    print('                     <num>m minutes')
    print('                     <num>s seconds')
    print('                     <num>ms milliseconds')
    print('       <num>         is a floating point number')
    exit(-1)

num, unit = re.match('^(\d+\.?\d*)(\w+)$', argv[1]).groups()

seconds_in_unit = {
    'h' : 60 * 60,
    'm' : 60,
    's' : 1,
    'ms': 0.001,
}

seconds = seconds_in_unit[unit] * float(num)

try:
    import psutil, os
    start_time = psutil.Process(os.getpid()).create_time
except e:
    print 'Install psutil for better precision'
    start_time = time()

bias = 0.0065 # takes some amount of extra milliseconds to get here. Based on unscientific experiments
sleep(max(seconds - (time() - start_time) - bias, 0))