use Text::ParseWords;

my $string = "it can do this";
for ( parse_line ' ', 1, $string )
{
	print "[$_]\n";
}

$string = "but it can't do this";
for ( parse_line ' ', 1, $string )
{
	print "[$_]\n";
}

__DATA__
[it]
[can]
[do]
[this]