http://www.perlmonks.org?node_id=282325

Provides a perl admin or user with the list (assuming CPAN.pm has been configured previously) of the mirror site URLs that will be queried when CPAN is next run.
Updated on November 7 2004
Updated on Mon, 25 Apr 2005 UTC: added url for netselect
#!/usr/bin/env perl # "dumpcpanurls" - list the mirrors CPAN.pm is configured to try $\=qq{\n}; use CPAN ; CPAN::Config->load ; print join qq{\n}, @{$CPAN::Config->{'urllist'}} ;

Same thing as a one-liner (*nix or MSwindoze):

perl -MCPAN -le "CPAN::Config->load; print join qq(\n)=> @{ \$CPAN::Co +nfig->{urllist} }" # remove this^ escape f +or windows shell

As a further (obvious) tip, note that this list can then be used as input into a pipeline, say to the ping(1) command, i.e.:

dumpcpanurls | perl -le 'do{s#^\w+p://([^/]+).*#$1#;print} for(<STDIN> +)' \ | xargs --max-args 1 ping -c 2
or to the netselect command if you have it:
dumpcpanurls | perl -le 'do{s#^\w+p://([^/]+).*#$1#;print} for(<STDIN> +)' \ | xargs netselect -vv
or doing this all in perl without the extra shell pipelines:
perl -MCPAN -le \ 'CPAN::Config->load; system "netselect", "-vv", map { s#^\w+p://([^/]+).*#$1# && $_ || ""} @{ $CPAN::Config->{urllist} } '
or a little more conservatively:
perl -MCPAN -le \ 'CPAN::Config->load; my @hosts; for (@{ $CPAN::Config->{urllist} }) { s#^\w+p://([^/]+).*#$1# && push @hosts => $_ } system("netselect", "-vv", @hosts) if @hosts'

It's Perl. TMTOWTDI :-)


Finding out that the first host in the list is down before running CPAN can be a Good Thing. Finding out which mirror seems fastest is also nice. ;-)