perl -e '@a=qw/z a r a z a a x/; $regex="|";foreach(@a){$regex.=$_."|
+" unless /^"$regex"$/ && $regex}@a=split /\|/, $regex; print @a'
[download]

PerlMonks lovingly hand-crafted by Tim Vroom.
PerlMonks was recently assimilated by The Perl Foundation.
Beefy Boxes and Bandwidth Generously Provided by pair Networks
Built with the Perl programming language.