In that case, see the answer below by Athanasius, about putting the value in a file. That's probably the simplest way to share a value between two programs that run independently of each other. You could write the value into the bash script directly, so it could pass it to script2.pl, but either way, you're writing the value into a file which can later be accessed in some way by the other script. So to keep it simple:

# in script1.pl
open my $out, '>', '/tmp/myvalue' or die $!;
print $out $final;
close $out;

# in script2.pl
open my $in, '<', '/tmp/myvalue' or die $!;
my $final = <$in>;
close $in;
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There's a potential issue here if you have multiple users possibly running both scripts at the same time. Potentially the value could be half-written at the moment that script2.pl tries to read it. If that's possible in your case, look into file locking or have the storage file in the user's home directory so there won't be a conflict between users.