#!/bin/sh
### Monitor free disk space
# Display alert if the free percentage of space is >= $ALERT

#
# Static Config Variables
#
ALERT=90                        # free space percentage to trigger an alert

#
# Static Binary Paths
#
DF='/bin/df'
GREP='/bin/grep'
AWK='/bin/awk'
CUT='/bin/cut'
HOSTNAME='/bin/hostname'
DATE='/bin/date'
OSD_CAT='/usr/bin/osd_cat'
export DISPLAY=:0.0
#
# Static System Variables
#
THIS_HOST=`${HOSTNAME}`

#
# Check CLI Options
#
VERBOSE=false
OSD=false
for ARG in "$@" ; do
        case $ARG in
        "-v")
                VERBOSE=true
                ;;
        "-osd")
                OSD=true
                ;;
        esac
done

#----------------------------------------------------------------------------
. /etc/osd_cat.cfg || {
    color=yellow
    outline=2
    outlinecolour=black
    shadow=0
    shadowcolour=black
    font="-adobe-helvetica-bold-*-*-*-34-*-*-*-*-*-*-*"
}
#----------------------------------------------------------------------------

[ $VERBOSE = true ] && echo "Checking free disk space on ${THIS_HOST}"
[ $VERBOSE = true ] && echo "Threshold for warning is ${ALERT}%"
[ $VERBOSE = true ] && echo "------------------------------------------------------------------"

# Dynamic Variables
#DATE_STR=`${DATE} "+%d-%B-%y @ %H%Mhrs"`

# Call df to find the used percentages. Grep for only local disks (not remote mounts like nfs or smb)
# Pipe the output to awk to get the needed columns, then start a while loop to process each line.
$DF -HPl | $GREP -E "^/dev/" | $AWK '{ print $5 " " $6 " " $1 }' | while read OUTPUT ; do
    USED_PCENT=$(echo ${OUTPUT} | $AWK '{ print $1}' | $CUT -d'%' -f1  )    # Used space as a percentage
    PARTITION=$(echo ${OUTPUT} | $AWK '{ print $2 }' )                      # Mount Point (eg, /home)
    DEVICE=$(echo ${OUTPUT} | $AWK '{ print $3 }' )                         # Device (eg, /dev/sda1 or LABEL or UUID)
    if [ $VERBOSE = true ] ; then
        echo -e "Checking device ${DEVICE} which is mounted to ${PARTITION} \t${USED_PCENT}% used"
    fi
    if [ ${USED_PCENT} -ge $ALERT ]; then
        if [ $VERBOSE = true ] ; then
            echo "WARNING: ${PARTITION} (${DEVICE}) is ${USED_PCENT}% full on ${THIS_HOST}."
        else
            echo "WARNING: ${PARTITION} (${DEVICE}) is ${USED_PCENT}% full on ${THIS_HOST}." #|
            if [ $OSD = true ] && [ ${PARTITION} = / ]; then
                echo "WARNING: The root (${PARTITION}) partition is ${USED_PCENT}% full on ${THIS_HOST}." | $OSD_CAT --pos=top --offset=40 --align=center --delay=10 --color=$color --outline=$outline --outlinecolour=$outlinecolour --shadow=$shadow --shadowcolour=$shadowcolour --font=$font &
            fi
        fi
    fi
done

exit 0