Use zone transfer to search for subdomains

dns.sh

#!/usr/bin/env bash

function aboutMe() {
    echo -e "\n\t${scriptName}, v ${scriptVersion}"
    echo -e "\n\tLooks through the ${lookupDomain} domain for what you want"
    echo -e "\n\tTreats spaces as '.*'"
    echo -e "\n\tExamples:"
    echo -e "\n\t${scriptFile}${Emphasize} rt vrdb${ColorOff} will match rt01.vrdb"
    echo -e "\t${scriptFile}${Emphasize} wireshark${ColorOff}\n"
    # echo -e "(behind the scenes, it's a fancy ${Emphasize} dig -t AXFR tekdom.local | grep${ColorOff})\n"
}

function colorInit() {
    ColorOff=$'\e[0m'       # Text Reset
    BWhite=$'\e[1;37m'      # Bold White
    BRed=$'\e[1;31m'        # Bold Red
    LGray=$'\e[0;37m'       # Light Gray

    if [ -z "$Diminish" ]; then
        Diminish=${LGray};
    fi
    if [ -z "$Emphasize" ]; then
        Emphasize=${BRed};
    fi
}

scriptFile=$(basename "${0}")
scriptName="DNS-looker-upper"
scriptVersion="2016-08-25 JAGR"
lookupDomain="tekdom.local."
undilutedSearch="$*"
searchTerms=${undilutedSearch/ /.*}

colorInit

if [ "$#" -lt 1 ]; then
    aboutMe;
    exit
fi

dig -t AXFR ${lookupDomain} |\
 sort |\
 awk '{ print $5 "\t" $1 }' |\
 tr '[:upper:]' '[:lower:]' |\
 grep -i "${searchTerms}" |\
 sed "s/\(${lookupDomain}\)/${Diminish}\1${ColorOff}/g"