perl -e "@re='abcdefg'=~/(..)/g;print join ',', @re;"
#prints ab,cd,ef 
##</code><code>##

perl -e "$_='abcdefg';@re=/(..)(?{reverse;chop;reverse;})/g;print join ',', @re;"
ab,cd,
perl -e "$_='abcdefg';@re=/(..)(?{$_=substr($_,1)})/g;print join ',', @re;"
bc,ef,