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For string "aa\nbb\ncc" I want to match from the last letter left to the first newline ("a") to the end of the multi line string and expected that "aa\nbb\ncc" =~ qr/( . $ .+ )/xms matches a\nbb\ncc and that "aa\nbb\ncc\n" =~ qr/( . $ .+ )/xms matches a\nbb\ncc\n . But I got no match for "aa\nbb\ncc" =~ qr/( . $ .+ )/xms and match c\n for "aa\nbb\ncc" =~ qr/( . $ .+ )/xms . Using qr/( . $ ..+ )/xms I got the expected results (see example code). Perl version 5.14.2. Can anyone give an explanation for that behaviour? perldoc perlre: m Treat string as multiple lines. That is, change "^" and "$" from matching the start or end of the string to matching the start or end of any line anywhere within the string. s Treat string as single line. That is, change "." to match any character whatsoever, even a newline, which normally it would not match. Used together, as "/ms", they let the "." match any character whatsoever, while still allowing "^" and "$" to match, respectively, just after and just before ewlines within the string. \z Match only at end of string Running the following example code : #!/usr/bin/env perl use strict; use warnings; print "Multiline string : ", '"aa\nbb\ncc"', "\n\n"; my $str = "aa\nbb\ncc"; print_match($str, qr/( . $ )/xms); # matches "a" print_match($str, qr/( . $ . )/xms); # matches "a\n" print_match($str, qr/( . $ .. )/xms); # matches "a\nb" print_match($str, qr/( . $ ..+ )/xms); # matches "a\nbb\ncc" print_match($str, qr/( . $ .+ )/xms); # NO MATCH ! Why ??? print_match($str, qr/( . $ .+ \z )/xms); # NO MATCH ! Why ??? print "\nMultiline string now with terminating newline : ", '"aa\nbb\ncc\n"', "\n\n"; $str = "aa\nbb\ncc\n"; print_match($str,

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