Gather `ps` output sorted by memory usage and log to a file

ps_logger.py

import datetime
import sys
import time
from subprocess import check_output

try:
    filename = sys.argv[1]
except IndexError as e:
    print "Must specify a filename."
    sys.exit(1)

while True:
    with open(filename, "a") as f:
        output = check_output("ps aux --sort -rss".split(" "))
        timestamp = datetime.datetime.fromtimestamp(
            time.time()
        ).strftime('%Y-%m-%d %H:%M:%S')

        f.write("\nTIMESTAMP: {}\nTOP OUTPUT:\n{}\n".format(timestamp, output))
        time.sleep(1800)