"Why use perl? Most powerful onliners one-liners".
Two examples produce an error: print $var";
"{m,n} Match atleast at least n m times but not more than m n times."
"(?(?<!) Match if expr wouldn't match previously."
"We have to define the handler in capital letters but its it's not manditory mandatory." (In addition to typos, "have to" and "not mandatory" are conflicting.)