title: How to change the perl cpan repository location
body: <p>When I am using cpan to install module, there is a download source which is very unstable and slow, and I might want to install that module on many machines?</p>
  
  <p>Is that possible to change the perl module repository to other address, or copy the repos to local disk.</p>
  
  <p>Or, can we save the local module files to local when we use cpan. It seems cpan would delete it after installation.</p>