open(IN, "/some/file") || die "Cant open /some/file: $!\n";
while (<IN>) {
   push(@foo, $_) if ( m/^$match/ );
}
close(IN);

# as opposed to

open(IN, "/some/file") || die "Cant access /some/file: $!\n";
@foo = grep(m/^$match/, <IN>);
close(IN);