This works ---> it will run as a cgi program and display 'hello' in the browser; now, if I add one line in the beginning use LWP::Simple; it will work in the command line, but if I try to display 'hello' in the browser, it will automatically redirect to some 'foo.example.com' and tell me 'This page cannot display'. Thanks to others for all the replies. I reply this one as it is easier for me to describe the problem.