$ perl -e '
> $str = q{abcXghiXstu};
> @elems = split m{X}, $str;
> print qq{$_\n} for @elems;'
abc
ghi
stu
$ perl -e '
> $str = q{abcXghiXstu};
> @elems = split m{(X)}, $str;
> print qq{$_\n} for @elems;'
abc
X
ghi
X
stu
$