whynosleep.sh

#!/bin/sh

# Source: http://hints.macworld.com/article.php?story=20120701234338952
# Have you ever been annoyed to find that your Mac won't got to sleep when you tell it to?
# It turns out that in Mac OS X 10.6 and later, there's a simple way of finding out what's
# keeping your Mac awake. 

# Run the following command in your Terminal: 

# pmset -g assertions 

# In the first section of output, you'll see the status of two kernel assertions named
# PreventSystemSleep and PreventUserIdleSystemSleep. An accompanying status of 1 for
# either of these means that it is currently triggered. 

# The second section of the output lists the processes which owns any enabled assertions,
# both by process id (pid) and bundle id. If the verbose bundle id doesn't ring a bell,
# you can always use ps up <pid>, or look in Activity Monitor, to find the name of the
# exact command associated with this process.

pmset -g assertions