Another way to do it is to use ord and printf*:

    #!/usr/bin/perl -wl
    use strict;

    my $char = '~';

    print            ord $char;
    printf "%08b\n", ord $char;


    __END__
    Prints:

    126
    01111110
[download]

* The "%b" format is only available with perl5.6 or later.

--
John.