This one is pretty simple trick.. in ubuntu whenever i want to use internet i use wvdial. it is a simple tool to make a connection by ppp dialing. i'm using really a bad network.. :( it will sometimes automatically disconnect.. morever it will not make my connection quickly.. i have to use the command sudo wvdial repeatedly.. sometimes more than 7 or 8 times.. so this simple command help me to resolve this problem. we have to use while loop to do this command infinite times. just type