TITLEPractice Assignment 1

The purpose of this assignment is to practice merging data from two files to generate a report.

The two files to merge are:

snmp.txt
SNMP messages from an appliance router that define the start of a conversation between a node on the inside of the local network and a node in the outside world.

This message includes the local port assigned to this conversation. This port will be unique for each conversation in these files.

tcpdump.txt
Output from a TCP sniffer attached upstream of the appliance router.

These messages show details about each packet that is transfered between the router and the external nodes including the time, number of bytes, IP addresses and IP port the packets are transferred between.

Write an application that reads these two files and generates a report by examining each line in the SNMP file and finding all the lines in the tcpdump file that relate to that conversation (have the same port address).

Total the number of bytes sent and received in the conversation and generate a report that looks like this: 


Time		Rcv	Xmit	Internal		External		Service Port
16:02:14	7723	2999	192.168.1.2	->	mail.emich.edu 	443
16:02:19	534	2183	192.168.1.2	->	0.channel41.facebook.com 	80
16:02:40	20247	1098	192.168.1.249	->	204.176.49.116 	80
16:03:17	534	2183	192.168.1.2	->	0.channel41.facebook.com 	80
16:04:15	534	2181	192.168.1.2	->	0.channel41.facebook.com 	80

There are some options to the lsearch command that will be required to finish this assignment:

Syntax: lsearch ?-behavior? list pattern
There are several options to modify the normal behavior of the lsearch command
-all Return the indices of all elements that match the pattern
-start number Return the first element at or after index number
-inline Return the list elements that match the pattern, instead of the index number.

EXAMPLES 

set lst {a1 b2 c3 a4 b5 c6}
lsearch $lst a*
0
lsearch -start 1 $lst a*
6
lsearch -all $lst a*
0 6
lsearch -inline $lst a*
a1
lsearch -all -inline $lst a*
a1 a4

You will need either the -all or -start to solve this problem. Either option can be used sucessfully.

You don't need the -inline option, but using it will simplify your code.

solution