Welcome to the Monastery!

need help to connect switch 192.168.1.2 using perl script.

What switch are you talking about? What protocol does it use? SNMP? Telnet? SSH?

In perl script I want to use module (which i need to create) to reuse the code.

It's not necessary to create a module to resue the code, but anyway, read perlmod, perlnewmod, perlmodlib.

After connecting switch I need to excute "show running-config" and get the output.

I guess that this is a CISCO switch, right? You should have mentioned it (see How do I post a question effectively?). Try using some modules from CPAN.

Please provide me the script

Is PM a good place to get answers for homework?