Perhaps you're taking the wrong approach. If you want to take command line arguments and use them as parameters in an s/// statement, why not simply let the user enter the s/// statement as a whole? All you have to do is eval it.

If you have to call it often (thousands of times), you can simply wrap it in a sub to compile it. $_ can simply represent the sub's parameter. 

my $perl = shift;
$code = eval "sub { local \$_ = shift; $perl; return $_ }"
  or die "Syntax error: $@";
foreach my $var (@lots_of_data) { $var = $code->($var) }

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And in the end, you give the user the option to pass in other code than just a simple s///. This is something that the module File::Rename does, for example, a command line utility to rename files where you can define how the file name should be named in a Perl snippet that changes the value of $_ (the file name).

In reply to Re: hex code passed from command line is interpreted literally in substitution by bart
in thread hex code passed from command line is interpreted literally in substitution by Allasso

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