New noob user problem

[BIG-FAN]

im on raspbian on raspberry pi3
on first run i got few errors telling to install File::HomeDir File::Pid Digest::MD4 im a noob so googled and did it like this

sudo perl -MCPAN -e 'install "File::HomeDir"' and so on with the rest but then i got a error saying

Can’t kill a non-numeric process ID at /usr/local/share/perl/5.14.2/File/Pid.pm line 124

i googled and got this https://www.omniweb.com/wordpress/?p=977 and did it

sudo nano that file and add "or return undef"

sub running {
my $self = shift;
my $pid = $self->_get_pid_from_file or return undef;

return   kill(0, $pid)
       ? $pid
       : undef;

}

and now it works thanks :)