my $literal = <DATA>;

  $literal =~ s/\\*'/\\'/g;

  # later on...

  # There may be a number of literals in reality - 
  # each would be single quoted to prevent interpolation

  my $string = eval "'$literal'";

  print $string, "\n";

__DATA__
this could be \x27; print system('ls -la'); \x27

##</code><code>##

>perl testcode.pl
this could be \x27; print system('ls -la'); \x27