How do I tell CPAN to install all dependencies?

Question

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.

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

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.

Changing the following parameter on top of prerequisites_policy follows.

cpan> o conf prerequisites_policy 'follow'
cpan> o conf build_requires_install_policy yes
cpan> o conf commit

This will change it from "ask/yes" to "yes" and stop it asking you.

Here's what I'm pretty sure you're looking for:

cpan> o conf prerequisites_policy follow
cpan> o conf commit

Maybe it's related to ExtUtils::AutoInstall or Module::AutoInstall being used. Try setting the PERL_AUTOINSTALL environment variable. (Cf. the documentation of those modules.)