[I want many plans and testcases to run by a single file. As Master plan-Sub plan are good medium since it gives me sharing features. Can anybody tell me how to run sub plans from the masterplan with an example.]

Yaa, you can run all your sub-plans using master plan approach.

You just open new plan file and call your subplan/testcase from this file.

if you want to run subplan from master plan then sysntax is like

include: mysubplan.pln