#!/bin/ksh

#   This script searches for file-systems with ocuppation greater than 90%
# If there is one or more file-systems in that condition, then knowledge the 
# System Administrators( $ADMIN variable ).
# 
#   I think that itīs a good idea to put this kind of monitoring script into
# the crontab. It can actually work with IBMīs AIX and SUNīs Solaris. Any 
# comments or enhancements are welcome.
# mail: tsuba@osite.com.br or humberto.tadashi.tsubamoto@br.abnamro.com

#   Set some variables necessari to create temporary files

TMPDIR=tmp
TMPARQ=monit_fs.tmp
ADMINS="root root"


#   This function is responsible for sending messages to System Administrators`
# terminal and sendim mail to their mailboxes.
alert ()
{
   for u_name in $ADMINS
   do

# Sends messages to an user Terminal.
      for terminal in `who | grep $u_name | awk '{print $2}'`
         do
         AUX=`who | grep $u_name`
         [ -z "$AUX" ] && continue
         write $u_name $terminal << EOF 2> /dev/null
         There are some file systems with capacity usage greater than 90%!!
         Look at your mailbox!!!
EOF
         done

# Sends mail to an user.
      mailx $u_name << EOF 2> /dev/null
The following file systems have used space greater than 90%!!
`cat /$TMPDIR/$TMPARQ`
.
EOF
  done
}

#   Unfortunately dfīs unix utility output is OS dependent. So this function
# looks at system type (AIX, SunOS) and exports a variable with the machineīs
# file-systems list
sist_op ()
{
   SO=`uname -s`
   case $SO in
      AIX   ) export LST_FS=`df -k |grep dev|awk '{print $7}'`
              ;;
      SunOS ) export LST_FS=`df -k |grep dev|awk '{print $6}'`
              ;;
      *     ) echo "Unknown Operating System!!!"
              exit 0
              ;;
   esac
}


#  According to system type (AIX, SunOS), sets the PERCENT variable with 
# percentual used space. (without % symbol)
perc ()
{
   case $SO in
      AIX   ) PERCENT=`df -k $FS|grep dev|awk '{print $4}' |sed "s/\%/""/g"`
            ;;
      SunOS ) PERCENT=`df -k $FS|grep dev|awk '{print $5}' |sed "s/\%/""/g"`
            ;;
      *     ) echo "Unknown Operating System!!!"
            exit 0
            ;;
   esac
}

#   Sets the CRITICAL variable, which determines if the alert() function will
# be executed.
CRITICAL=0
sist_op

#   Verify each file-system, putting in /$TMPDIR/$TMPARQ file the ones which 
# have ocuppation greater than 90%
for FS in $LST_FS
do
   perc
   if [ $PERCENT -gt 90 ] ; then
      echo "Ocupation in File System $FS is in $PERCENT%">>/$TMPDIR/$TMPARQ
      CRITICAL=1
   fi
done

#   If CRITICAL equal to 1 then there are file-systems with space problems. 
# So, we need to execute alert() function to knogedge the System Administrators
if [ $CRITICAL = 1 ] ; then
alert
fi 

#   Removes the temporary file
rm -f /$TMPDIR/$TMPARQ 2>/dev/null