use strict;
use warnings;
my $var = "-rw-rw-rw- 1 bsmbin bsmbin 303 Dec 4 23:00 BSC-20041204110000 -rw-rw-rw- 1 bsmbin bsmbin 303 Dec 4 23:00 20041204110000";

my ($transformed) = $var=~s/BSC-//;

print $var . " " . $transformed . "\n";