I'm trying to work out how Perl substitutions work. We're told that backreference patterns can be used in the substitution by specifying \1, \2 (etc), but it doesn't seem to work.

Snippet below. It tries to turn the string 'Hello sailor' into 'Goodbye sailor', but I get 'Goodbye \1' instead.

(Obviously this isn't sensible way to convert one string to the other, but this is just an example.)

#!/usr/bin/perl
use strict;
use diagnostics;
use warnings;

my $string = 'Hello sailor';
my $regex = 'Hello (.*)';
my $substitution = 'Goodbye \1';

$string =~ s/$regex/$substitution/;
print "string is now $string \n";

# I wanted:     string is now Good bye sailor
# I got:          string is now Good bye \1

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In reply to Substitution backreference woes by Anonymous Monk

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