#!/bin/sh

# big.cheese (Internet scanner in shell)
# 
# When run off a UNIX with Internet access, this program will scan for ALL
# computer systems tied to the network.  
# UNIX systems will be placed in a file called: .UNIX
# A complete listing of systems (including both UNIX and non-UNIX based
# systems will be found in: .ALL.SYSTEMS
# Please note: This is a *simplified* version written in approximately 1 hour.
#
if [ -z "$4" ]; then
  echo "\nUsage: big.cheese xxx xxx xxx xxx"
  exit
else
  prefix=$1;
  addr1=$2;
  addr2=$3;
  addr3=$4
fi

export prefix addr1 addr2 addr3

while :
  do
    if [ -f /tmp/stop.scn ]; then
      break
    fi
    echo "\n\r\n\r\n" | telnet "$prefix.$addr1.$addr2.$addr3" > /tmp/.chkit &
    sleep 10
    kill 0
    cat /tmp/.chkit >> .ALL.SYSTEMS
    
	x=`grep "login:" /tmp/.chkit`

	if [ "$x" ]; then
	  echo "`date` => $prefix.$addr1.$addr2.$addr3" >> .UNIX
    fi

	if [ $addr3 -gt 255 ]; then
      addr2=`expr $addr2 + 1`; addr3=0
	  if [ $addr2 -gt 255 ]; then
        addr1=`expr $addr1 + 1`; addr2=0
        if [ $addr1 -gt 255 ]; then
          DONE=1
        fi
      fi
    fi
done