last_patch() {

	## returns the number of patches installed at or above this rev.
        ## if this is the first rev of the patch
        ##      prepatch will return 0
        ##      postpatch, prebackout, and postbackout will return 1


	root_dir=${ROOTDIR:-/}

	## parse id and rev
	pid=`echo $1 | cut -d\- -f1`
	prev=`echo $1 | cut -d\- -f2`
	patch_cnt=0

	## get all installed refernces to the installed patch base id	
	installed_patches=`patchadd -p -R $root_dir -p | sed -n -e 's/Req.*//' -e 's/[a-zA-Z]*://g' -e 's/,//g' -e "/$pid/p"`
	
	for x in $installed_patches ; do
		base=`echo $x  | cut -d\- -f1`
		rev=`echo $x | cut -d\- -f2`
		if [ $pid -eq $base ] && [ $rev -ge $prev ] ; then 
			## count all installed patches includeing this patch
			patch_cnt=$(($patch_cnt + 1))
		fi
	done
	
	return $patch_cnt
}