Write a CGI program that keeps a list of computers that have contacted the server. If comp1 is contacting first time it will display the message:

"This is the first contact from comp1" else it will display the message

"Computer comp1 has requested this URL previously."

A CGI program which has a list of computers which have contacted the server is as given below:

#!/bin/sh

FILE = ipaddress

echo Content -type: text /plain

echo

# see if IP address computer appears in file ip address

if grep -s $REMOTE_ADDR $FILE>/dev/nul l 2 >&1

then

echo Computer $REMOTE_ADDR has requested this URL previously.

else

# append browser's address to the file

echo $REMOTE_ADDR >> $FILE

echo This is the first contact from computer $REMOTE_ADDR.