How do I tell CPAN to install all dependencies?

Here is the one-liner making these changes permanent including automatic first-time CPAN configuration:

perl -MCPAN -e 'my $c = "CPAN::HandleConfig"; $c->load(doit => 1, autoconfig => 1); $c->edit(prerequisites_policy => "follow"); $c->edit(build_requires_install_policy => "yes"); $c->commit'

Or combine it with local::lib module for non-privileged users:

perl -MCPAN -Mlocal::lib=~/perl5 -e 'my $c = "CPAN::HandleConfig"; $c->load(doit => 1, autoconfig => 1); $c->edit(prerequisites_policy => "follow"); $c->edit(build_requires_install_policy => "yes"); $c->commit'

Run it before using the CPAN shell or whatever.

The latest and greatest answer to this question is to use cpanm instead (also referred to as App::cpanminus or cpanminus)!

DESCRIPTION

cpanminus is a script to get, unpack, build and install modules from CPAN and does nothing else.

It's dependency free (can bootstrap itself), requires zero configuration, and stands alone. When running, it requires only 10MB of RAM.

To bootstrap install it:

curl -L http://cpanmin.us | perl - --sudo App::cpanminus

or if you are using perlbrew simply

perlbrew install-cpanm

or from cpan itself:

cpan install App::cpanminus

From then on install modules by executing (as root if necessary)

cpanm Foo::Bar

Try setting PERL_MM_USE_DEFAULT like so:

PERL_MM_USE_DEFAULT=1 perl -MCPAN -e 'install My::Module'

It should make CPAN answer the default to all prompts.