Sounds like golf! First, a not-that-obfuscated version that emulates cut -cSPEC:

#!perl -lp

BEGIN {
    $s = shift
}

sub cut
{
    my ($s, $r) = pop;
    for (split /,/, shift) {
        $r .= /(\d+)-(\d+)/ ? substr $s,$1-1,$2-$1+1 : substr $s, $_-1
+,1;
    }
    $r;
}

chomp;
$_=cut $s, $_;
[download]

Alright, now let's get started with a 104 96:

#!perl -lp
BEGIN{@s=split/,/,shift}
chomp;
$x=$_;
/(\d+)-?/,
$r.=substr$x,$1-1,($'||$1)-$1+1
for@s,$r='';
$_=$r
[download]

...or 73:

#!perl -ln
BEGIN{($s=shift)=~s/-/../g}
chomp;
$x=$_;
print+map{substr$x,$_-1,1}eval$s
[download]