list domain as seen in a web page

#!/usr/bin/env bash
##variables
domain_mirror=$domain.txt
domain=$1
##functions go here

##banner function
banner()
{
echo -e "\033[34m\t\t#############################################
\t\t##this script search for domains and subdomain ##
\t\t##        as seen from a given website         ##
\t\t##           inspiration:list-urls.py          ##
\t\t##        author:plast1k                       ##
\t\t##+++++++++++++++++++++++++++++++++++++++++++++##
\033[0m"

}

##usage function
usage()
{
echo -e ""
echo -e "USAGE: $./list_domains.sh domain"
echo -e "example: user@box:~$./list_domain.sh mysite.com"
echo -e ""
}

##download function
download()
{
wget http://$domain -O $domain_mirror -o /dev/null
}

##matching_domain_purser function
matching_domain_purser()
{
grep "href=" $domain_mirror  | cut -d "/" -f 3 | grep $domain | sort -u | cut -d " " -f 1 | sed s'/\"//g' | sort -u | sed s'/ //g'
}

##unmatching_domain_purser function
unmatching_domain_purser()
{
grep "href=" $domain_mirror  | cut -d "/" -f 3 | cut -d " " -f 1 | grep "\." | sed s'/"//g' | sort -u | grep -v $domain | egrep -v  '[!,@,#,$,%,^,&,*,(,),{,},[,[,<,>,?,=]'
}

##results display function
display()
{
echo -e "getting a local copy of $domain index page.........."
download
echo -e "Done!"
echo -e ""
echo -e "\033[31mrelated domains found on http://www.$domain\033[0m"
echo -e ""
matching_domain_purser
echo -e ""
echo -e "\033[31mother domains found on http://www.$domain \033[0m"
echo -e ""
unmatching_domain_purser
echo -e ""
}

##clean up function
clean_up()
{
rm  -rf $domain_mirror
}

##master function
master()
{
banner
display
clean_up
}

###################################
########script entrance############
if [ $# == 1 ]
then
#run call master
master
else
banner
usage
fi