You access GNU Readline variables through the Attribs method (with the rl_ stripped). Term::ReadLine::Gnu_Variables

#!/usr/bin/perl
use strict;
use warnings;
use Term::ReadLine;

$SIG{TERM} = sub { print "I got a TERM\n"; exit; };
$SIG{INT} = sub { print "I got a INT\n"; exit; };
# add any additional signal handlers you want

my $term = Term::ReadLine->new('Term1');
$term->ornaments(0);
my $attribs = $term->Attribs;
$attribs->{catch_signals} = 0; # the default is 1
my $prompt = 'cmd> ';
while ( defined (my $cmd = $term->readline($prompt)) ) {
    chomp($cmd);
    if ($cmd =~ /^help$/) {
        print "Help Menu\n";
    }
    else {
        print "Nothing\n";
    }
}
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Update: Added $SIG{INT}