Geolocate ip addresses in a raw apache log (still needs revisions)

#!/usr/bin/env bash
# requires geoiplookup, do "brew install geoip"
# and  brew install geoiplookup
# this is how to extract ip addresses and the count of occurances
# egrep -o '[0-9]+(\.[0-9]+){3}' < accesslog.txt | sort | uniq -c | sort -nr > access.txt
# specify the output access.txt as an argument,
if [ $# -ne 1 ]; then
  echo "$# argument specified" 1>&2
  echo "this script requires 1 argument" 1>&2
  exit 1
fi

numLine=1
cat $1 | while read line
do
	ipaddress=`echo ${line} | grep -Eo "[0-9]+(\.[0-9]+){3}"`
	geoipdata=`geoiplookup ${ipaddress} | cut -f2 -d ','| sed -e 's/^[ \t]*//'`
	echo \#$numLine: $line $geoipdata
	numLine=$((numLine + 1))
done

#memo
# select any lines with a specific domain
# ^(?!.*http://(subdomain1|subdomain2).domain.com/).+$