text: #! /usr/bin/python
  
  from __future__ import print_function
  
  import locale
  import random
  import time
  from math import sin
  
  import rrdtool
  
  start = int(time.time())
  rrd = 'random.rrd'
  
  rrdtool.create(rrd,
                 '--start', str(start-1),
                 '--step', '300',
                 'DS:a:GAUGE:600:U:U',
                 'DS:b:GAUGE:600:U:U',
                 'RRA:AVERAGE:0.5:1:200')
  
  for t in range(start, start+200*300, 300):
      rrdtool.update(rrd, '%s:%s:%s' % (
          t,
          random.randint(0, 100),
          sin(t/800.)*50+50))
  
  locale.setlocale(locale.LC_ALL, '')  # enable localisation
  
  rrdtool.graph('stripes.png',
                '--title', 'Stripes Demo',
                '--start', str(start),
                '--end', str(start+400*60),
                '--interlace',
                '--imgformat', 'PNG',
                '--width=450',
                'DEF:a=%s:a:AVERAGE' % rrd,
                'DEF:b=%s:b:AVERAGE' % rrd,
                'CDEF:alpha=TIME,1200,%,600,LT,a,UNKN,IF',
                'CDEF:beta=TIME,1200,%,600,GE,b,UNKN,IF',
                'AREA:alpha#0022e9:alpha',
                'AREA:beta#00b674:beta',
                'LINE1:b#ff4400:beta envelope\\c',
                'COMMENT:\\s',
                'COMMENT:alpha=TIME,1200,%,600,LT,a,UNKN,IF',
                'COMMENT:beta=TIME,1200,%,600,GE,b,UNKN,IF\\j')
  
  print('This script has created stripes.png in the current directory')
  print('This demonstrates the use of the TIME and % RPN operators')
  