perl -e "$_='qwerty'; s/r/print pos(). \"\n\";/e; print $_;"
syntax error at -e line 2, near "="
Execution of -e aborted due to compilation errors.

##</code><code>##

perl -e "\$_='qwerty'; s/r/print pos(). \"\n\";/e; print \$_;"
3
qwe1ty

##</code><code>##

perl -e "\$_='qwerty'; s/r/print pos(). \"\n\";\$&/e; print \$_;"
3
qwerty