#!/bin/bash
tempFileName=${1:-file}

    awkExtractIPAddresses='
    BEGIN {
        ipSequence = "[0-9]+[.][0-9]+[.][0-9]+[.][0-9]+"
        digitSequenceTooLongNotIP = "[0-9][0-9][0-9][0-9]+"
        encInFwdSlashesNotIP = "[/]" ipSequence "[/]"
        versioningNotIP = "[Vv]([Ee][Rr]([Ss][Ii][Oo][Nn])?)?[ .]*" ipSequence
    }
    {
        line = $0
        gsub(digitSequenceTooLongNotIP, "x", line)
        gsub(encInFwdSlashesNotIP, "x", line)
        gsub(versioningNotIP, "x", line)
        while (match(line, ipSequence)) {
            ip = substr(line, RSTART, RLENGTH)
            ipUnique[ip]
            line = substr(line, RSTART + RLENGTH + 1)
        }
    }
    END {
        ipRangeMin = 0
        ipRangeMax = 255
        ipNumSegments = 4
        ipDelimiter = "."
        for (ip in ipUnique) {
            numSegments = split(ip, ipSegments, ipDelimiter)
            if (numSegments == ipNumSegments &&
                ipSegments[1] >= ipRangeMin && ipSegments[1] <= ipRangeMax &&
                ipSegments[2] >= ipRangeMin && ipSegments[2] <= ipRangeMax &&
                ipSegments[3] >= ipRangeMin && ipSegments[3] <= ipRangeMax &&
                ipSegments[4] >= ipRangeMin && ipSegments[4] <= ipRangeMax) {
                    print ip
            }
        }
    }'

    ipAddressMatches=$(awk "$awkExtractIPAddresses" "$tempFileName")

printf "%s\n" $ipAddressMatches