Reads you log files in syslog format like /var/log/syslog and shows log activity in hours per day

czasomierz.py

#!/usr/bin/env python
# usage: sudo ./czasomierz.py /var/log/syslog*

from datetime import datetime, timedelta, date, time
import sys
import gzip
from itertools import groupby

def parse_date(line):
    fields = line.split()
    return fields[:3]

def smart_open(fn):
    return gzip.open(fn) if fn.endswith('.gz') else open(fn)

def main():
    fns = sys.argv[1:]
    files= [smart_open(fn) for fn in fns][::-1] or [sys.stdin]
    lines = [line for f in files for line in f]
    dates = [parse_date(line) for line in lines]
    dates_day = groupby(dates, lambda x: x[1])
    for group, grouper in dates_day:
        lst = list(grouper)
        start = lst[0]
        end = lst[-1]
        start_time = datetime.strptime(start[2], '%H:%M:%S')
        end_time = datetime.strptime(end[2], '%H:%M:%S')
        duration = end_time - start_time
        print '%-40s%-40s%-40s' % (start, end, duration)
        

main()