$ echo $SHELL
/bin/bash

##</code><code>##

cpan> o conf shell
    shell              /bin/bash

##</code><code>##

$ perl -MRRDs -e1

##</code><code>##

$ perl -MRRDs -e1  
Can't locate RRDs.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.8.4 /usr/local/share/perl/5.8.4 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.8 /usr/share/perl/5.8 /usr/local/lib/site_perl .).
BEGIN failed--compilation aborted.