The regular expression in Perl is the pattern that provided a flexible concise mean to match a string in Perl.Transition and substitution is similar to sed command which was used in a Linux.Below is the syntax of the translation operator in Perl is as follows.But translation is not used in regular expression or search on replacement values. The translation operator is similar to the substitution operator in Perl.Below is the syntax of the substitution operator in Perl is as follows.It is used to match the replacement of text matched with the new text which we have used in code.Substitution operator in Perl just the extension of a matched operator.We have used Perl matching operator =~ and !~ to match the word given from the string. x – It is used white space in the expression.