His example, slightly modified for Perl: my $emailPattern = qr{ ^ #begin of line ([a-z0-9_.-]+) #one or more letters, numbers, _ . or - @

His example, slightly modified for Perl: my $emailPattern = qr{ ^ #begin of line ([a-z0-9_.-]+) #one or more letters, numbers, _ . or - @ #followed by an @ sign ([\da-z.-]+) #then one or more letters, numbers, _ . or - \. #followed by a period ([a-z.]{2,6}) #followed by 2 to 6 letters or periods $ }xi; #end of line and ignore case if( 'john.smith@gmail.com' =~ $emailPattern ){ print "E-mail is valid\n"; } else { print "E-mail is invalid\n"; } EDIT: A much better way of doing it though: use Mail::Sendmail; if( 'john.smith@gmail.com' =~ /$Mail::Sendmail::address_rx/ ){ print "E-mail is valid\n"; } else { print "E-mail is invalid\n"; }