Zero-width assertions like  ^, $, \A, \Z, \z, \b, \B and \G match at a position in a string, they do not match a character.   So  $ and \Z will normally match at the position before the newline at the end of the string unless a) there is no newline at the end of the string, or b) the pattern before the assertion would also match a newline. 

$ perl -e'
use Data::Dumper; $Data::Dumper::Useqq = 1;
for ( "ab\ncd", "ab\ncd\n" ) {
    /\w*$/  && print Dumper $&;
    /\w*\Z/ && print Dumper $&;
    /.*$/   && print Dumper $&;
    /.*\Z/  && print Dumper $&;
    /.*$/m  && print Dumper $&;
    /.*\Z/m && print Dumper $&;
    /.*$/s  && print Dumper $&;
    /.*\Z/s && print Dumper $&;
    print "\n";
    }
'
$VAR1 = "cd";
$VAR1 = "cd";
$VAR1 = "cd";
$VAR1 = "cd";
$VAR1 = "ab";
$VAR1 = "cd";
$VAR1 = "ab\ncd";
$VAR1 = "ab\ncd";

$VAR1 = "cd";
$VAR1 = "cd";
$VAR1 = "cd";
$VAR1 = "cd";
$VAR1 = "ab";
$VAR1 = "cd";
$VAR1 = "ab\ncd\n";
$VAR1 = "ab\ncd\n";

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Also, you are using the /s modifier which only effects whether the . metacharacter will match a newline or not, and you are not using the . metacharacter in your patterns.

In reply to Re: When exactly do Perl regex's require a full match on a string? by jwkrahn
in thread When exactly do Perl regex's require a full match on a string? by ELISHEVA

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