BEGIN {

  if (ARGC != 2) {

    print "URLCHK - check if URLs have changed"

    print "IN:\n    the file with URLs as a command-line parameter"

    print "    file contains URL, old length, new length"

    print "PARAMS:\n    -v Proxy=MyProxy -v ProxyPort=8080"

    print "OUT:\n    same as file with URLs"

    print "JK 02.03.1998"

    exit

  }

  URLfile = ARGV[1]; ARGV[1] = ""

  if (Proxy     != "") Proxy     = " -v Proxy="     Proxy

  if (ProxyPort != "") ProxyPort = " -v ProxyPort=" ProxyPort

  while ((getline < URLfile) > 0)

     Length[$1] = $3 + 0

  close(URLfile)      # now, URLfile is read in and can be updated

  GetHeader = "gawk " Proxy ProxyPort " -v Method=\"HEAD\" -f geturl.awk "

  for (i in Length) {

    GetThisHeader = GetHeader i " 2>&1"

    while ((GetThisHeader | getline) > 0)

      if (toupper($0) ~ /CONTENT-LENGTH/) NewLength = $2 + 0

    close(GetThisHeader)

    print i, Length[i], NewLength > URLfile

    if (Length[i] != NewLength)  # report only changed URLs

      print i, Length[i], NewLength

  }

  close(URLfile)

}