#! /bin/sh
# ckspace (Bourne shell script) -- report if any filesystem's free space is too low
# Version 1.0
#
# Copyright (C) 2012 Alastair Irvine <alastair@plug.org.au>
# Warpspace IT <http://www.warpspace.net/>
# 
#     This program is free software; you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation; either version 2 of the License, or
#     (at your option) any later version.
# 
# On Debian systems, the complete text of the GNU General Public License
# can be found in `/usr/share/common-licenses/GPL'.
#
#
# TO-DO: support Darwin

df_opts="-k"
threshold=75

# df's output is wrapped sometimes, so merge each filesystem's output onto one line
merge_lines ()
{
  # if there is a line with just one field, then it is a long device name
  # so save it and print this device field at the start of the next line
  awk 'NF > 1  { 
                 # this line might hold everything but the device
                 # (if the device was too long it was on the previous line)
                 if (stashed_dev) 
                   { 
                     print stashed_dev " " $0;
                     stashed_dev=0;
                   }
                 else 
                   print $0;
               }
       NF == 1 { 
                 # this line holds just a long device name
                 stashed_dev=$1 
               }'
}


# *** MAINLINE ***
case `uname -s` in
  Darwin)
    echo MacOS X not supported >&2
    exit 3
    ;;

  FreeBSD)
    df_opts="$df_opts -t ufs"
    ;;

  Linux)
    df_opts="$df_opts -l -x tmpfs"
    ;;

  Solaris)
    df_opts="$df_opts -l"
    ;;

  *) echo Unix release `uname -s` not supported >&2
    exit 3
esac

# run df and iterate over the mount points
df $df_opts | merge_lines | while read dev size used avail capacity mount_point ; do
  if [ $dev = Filesystem ] ; then
    continue
  fi
  # remove the first percent character and everything after it
  percent_used=${capacity%%%}
  # check the usage of this mount point
  if [ $percent_used -gt $threshold ] ; then 
    echo $mount_point is $capacity used!
  fi
done