perl -MCPAN -e shell

##</code><code>##

...:/Users/nick/perl5/perlbrew/perls/perl-5.6.0/bin:...:/usr/bin:...

##</code><code>##

$ which perl
/Users/nick/perl5/perlbrew/perls/perl-5.6.0/bin/perl
$ which cpan
/usr/bin/cpan