How can I search and replace text that looks like Perl variables?

Question

I'm really getting my butt kicked here. I can not figure out how to write a search and replace that will properly find this string.

String:

$QData{"OrigFrom"} $Text{"wrote"}:

Note: That is the actual STRING. Those are NOT variables. I didn't write it.

I need to replace that string with nothing. I've tried escaping the $, {, and }. I've tried all kinds of combinations but it just can't get it right.

Someone out there feel like taking a stab at it?

Thanks!

Answer 1

No one likes quotemeta ? Let Perl figure it out so you don't strain you eyes with all those backslashes. :)

 my $string = 'abc $QData{"OrigFrom"} $Text{"wrote"}: def';
 my $escaped = quotemeta '$QData{"OrigFrom"} $Text{"wrote"}:';

 $string =~ s/$escaped/Ponies!/;

 print $string;

Answer 2

I originally thought that wrapping your regex in \\Q / \\E (the quotemeta start and end escapes) would be all that you needed to do, but it turns out that $ (and @ ) are not allowed inside \\Q...\\E sequences (see http://search.cpan.org/perldoc/perlre#Escape_sequences ).

So what you need to do is escape the $ characters separately, but you can wrap everything else in \\Q ... \\E :

/\$\QQData{"OrigFrom"} \E\$\QText{"wrote"}:\E/

Answer 3

regex using escape character \\ would be

s/\\$QData\\{"OrigFrom"\\} \\$Text\\{"wrote"\\}://;

full test code:

#!/sw/bin/perl     

$_='$QData{"OrigFrom"} $Text{"wrote"}:';

s/\$QData\{"OrigFrom"\} \$Text\{"wrote"\}://;

print $_."\n";

outputs nothing but newline.