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Python: Uptime script

I've been writing Python for a grand total of 2 days. I recently wrote a little Python script to print a Linx or UNIX system's uptime. This took about 10 minutes to write, so I was pretty pleased. It even runs well on a 75MHz Busybox embedded Linux system. Check it out:

PLAIN TEXT
PYTHON:
  1. #!/usr/bin/python
  2. import os
  3.  
  4. #----------------------------------------
  5. # Gives a human-readable uptime string
  6. def uptime():
  7.  
  8.      try:
  9.          f = open( "/proc/uptime" )
  10.          contents = f.read().split()
  11.          f.close()
  12.      except:
  13.         return "Cannot open uptime file: /proc/uptime"
  14.  
  15.      total_seconds = float(contents[0])
  16.  
  17.      # Helper vars:
  18.      MINUTE  = 60
  19.      HOUR    = MINUTE * 60
  20.      DAY     = HOUR * 24
  21.  
  22.      # Get the days, hours, etc:
  23.      days    = int( total_seconds / DAY )
  24.      hours   = int( ( total_seconds % DAY ) / HOUR )
  25.      minutes = int( ( total_seconds % HOUR ) / MINUTE )
  26.      seconds = int( total_seconds % MINUTE )
  27.  
  28.      # Build up the pretty string (like this: "N days, N hours, N minutes, N seconds")
  29.      string = ""
  30.      if days> 0:
  31.          string += str(days) + " " + (days == 1 and "day" or "days" ) + ", "
  32.      if len(string)> 0 or hours> 0:
  33.          string += str(hours) + " " + (hours == 1 and "hour" or "hours" ) + ", "
  34.      if len(string)> 0 or minutes> 0:
  35.          string += str(minutes) + " " + (minutes == 1 and "minute" or "minutes" ) + ", "
  36.      string += str(seconds) + " " + (seconds == 1 and "second" or "seconds" )
  37.  
  38.      return string;
  39.  
  40. print "The system uptime is:", uptime()

One interesting thing about this script is its emulation of the C ternary operator using Python's short-circuited "and" operator. Notice this bit:

PLAIN TEXT
PYTHON:
  1. (days == 1 and "day" or "days" )

Python doesn't have the C-style ternary operator:

PLAIN TEXT
C++:
  1. (days == 1 ? "day" : "days")

So the short-circuited "and" is a decent alternative. Instead of ignorantly printing "1 days", this code will actually print "1 day" and "2 days" like it should.

This entry was posted on Saturday, November 19th, 2005 at 10:16 am and is filed under Code and Cruft. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

4 Responses to “Python: Uptime script”

  1. Jesse Says:
    April 16th, 2006 at 2:41 am

    Nice script! I am going to use it in a script I am writing for my backup server at home (open Source of course). You saved me a lot of time.

  2. Filip Says:
    January 28th, 2007 at 12:05 pm

    Thanks for the nice hack with ternary operator, I was searching for it for a while now.
    The script is nice to, though you might mention that, in order to be able to call it “uptime” instead of “python uptime” a line “#!/path/to/python/interpreter” should be added (it also took me a while to figure this out in the beginning).

  3. Dave Says:
    January 28th, 2007 at 12:31 pm

    This was meant as an example code snippet that others could use in their Python programs, not as a stand-alone script. For that purpose, I would just use the “uptime” command.

    –Dave

  4. Friedmud Says:
    September 6th, 2007 at 6:46 am

    Thanks for the idea… I was just getting ready to call “uptime” via ssh to get the load average on a bunch of machines…. but after seeing this script I noticed that all I have to do is something like:

    file = os.popen(’ssh machine_name “cat /proc/loadavg”‘)
    contents = file.read().split()
    print contents[0]

    Which is much easier!

    Friedmud

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