Mar 10 2004 - There's a decent amount one can accomplish with basic shell scripting, though you reach your limits eventually with what you can do with sed/awk and so some perl code sneaks into here.. which is a network management utility i wrote while at an internet service provider for creating index pages from a set of mrtg-monitored devices

rewalk.sh

#!/usr/local/bin/bash

if [ X"$(whoami)" != "Xroot" ]
then
	echo "This program now must be run as root.."
	exit
fi

INTERFACES='cs1 cs2 cs3 cs4 cs5 cs7 cs8 cs9 cs10 cs11 cs12 cs13 cs14 cs15 cs20 cs20b cs21 cs22 cs23 cs24 cs25 cs30 cs30b cs40b csmarigold core01 core02 core04 core05 core06'
WALKDIR="/home/cricket/walk"
WORKDIR="/home/cricket/mrtg"
COMMUNITY="nyinet"
CONF="$COMMUNITY.cfg"
LOCKFILE="$WALKDIR/.lock"

if [ -f $LOCKFILE ]
then
	echo "in the middle rewalking, cannot rewalk again until other walk finishes"
	exit
fi

touch $LOCKFILE
echo "rewalking the following interfaces: $INTERFACES"
for interface in $INTERFACES ; do
	interface_ip=$(host -t a $interface.nyi.net 2>/dev/null|awk '{print $4}')
	if [ $(grep -c $interface /etc/hosts) -eq 1 ]; then
		interface_ip=$(awk '/'"$interface"'/ {print $1}' /etc/hosts)
	fi
        if [ "X$interface_ip" != "X" ]; then
        	echo -n "now walking $interface ($interface_ip)...  "
		if [ -d $WALKDIR.old ]
		then
			cp $WALKDIR/$interface.raw $WALKDIR.old
		fi
		/usr/local/bin/cfgmaker ${COMMUNITY}@${interface_ip} \
			2> $WALKDIR/$interface.status 1> $WALKDIR/$interface.raw

                mkdir -p $WORKDIR/devices/$interface_ip
                echo -e "\tnow creating $interface.html..."
                perl -p -i -e '
			s@# WorkDir: /home/http/mrtg@WorkDir: '"$WORKDIR"'@' \
			$WALKDIR/$interface.raw

		if [ -d $WALKDIR.old ]
		then
			cp $WALKDIR/$interface $WALKDIR.old
		fi
                cat $WALKDIR/$interface.raw|awk '$1 !~ /^#/ && $1 !~ /^$/ {print}'|perl -e '
			while(<>) {
				chomp $_;
                                if (/^Target\[(([^]]+)_(\d+))\]: .+$/) {
                			$target = $1; $source = $2; 
					$number = sprintf("%03d",$3);
                			$source = "devices/$source/$number";
                			print; print "\n";
                			print "Directory[$target]: $source\n";
        			} else {
                			print; print "\n";
        			}
			}' > $WALKDIR/$interface

                /usr/local/bin/indexmaker --columns=1 --section=descr \
			$WALKDIR/$interface > $WORKDIR/devices/$interface.html

		perl -p -i -e '
			s#HREF="devices/#HREF="#; 
			s#SRC="devices/[^/]+/.../../devices/#SRC="#' \
			$WORKDIR/devices/$interface.html
        fi
done

mv $WALKDIR/$CONF $WALKDIR/$CONF.old
>$WALKDIR/$CONF

echo -n "now building $CONF using "
for interface in $INTERFACES ; do
	if [ -f $WALKDIR/$interface ]; then
		numLines=$(wc -l $WALKDIR/$interface|awk '{print $1}')
                tail -$[numLines-1] $WALKDIR/$interface >> $WALKDIR/$CONF
		echo -n "$interface "
	fi
done
if [ -f $WORKDIR/$CONF ]; then
	mv $WORKDIR/$CONF $WORKDIR/old/$CONF.$(date '+%y%m%d%H%M')
fi
cat $WORKDIR/mrtg.options $WALKDIR/$CONF > $WORKDIR/$CONF

if [ -x mrtg/threshold/thresholdUpdate.pl ]; then
	mrtg/threshold/thresholdUpdate.pl $WORKDIR/$CONF
	chown -R www mrtg/threshold/conf
fi

echo "... done."
chown -R cricket mrtg/devices
CHANGES="$(diff -u $WALKDIR/$CONF.old $WALKDIR/$CONF|egrep '^(\+|-)(SetEnv|Title)')"
if [ "X$CHANGES" != "X" ]
then
	echo
	echo "=== CHANGES DETECTED =="
	echo "Here's a list of changes made since the last walk:"
	echo "$CHANGES"
	echo "===== lines beginning with + are additions, lines beginning with - are deletions.. ======"
	echo
fi
echo "Restarting MRTG.. (PLEASE IGNORE ANY WARNINGS ABOUT A BAIL OUT, THIS IS NORMAL)"
/usr/local/etc/rc.d/mrtg.sh stop 2>/dev/null
sleep 1
/usr/local/etc/rc.d/mrtg.sh start

rm -f $LOCKFILE