y>reg export HKLM  cmd.reg
Operation completed succesfully.

lt@MC-TAVIANI:y>perl -e "system qq(reg export HKLM perl.reg)"
Operation completed succesfully.

y>dir *.reg

 Directory y:\

06/03/2015  08:54       191.906.582 cmd.reg
06/03/2015  08:54       191.906.582 perl.reg

##</code><code>##

my @rootk = qw(HKLM HKCU HKU HKCR);
foreach my $root ( @rootk ) {
        my $ile = $root.'.reg';
        system qq(reg export $root $file);
}