Struggle with "simple" replacement

[Arne]

Trying to make a simple replacement of strings I spent some hours
resulting in this:

#!/usr/bin/perl -w
#use strict;

$_ = "Just {Test4*4}";
#my $old = "{Test4*4}"; #(i) normal double quoted match
my $old = "\{Test4\*4\}"; #(ii) escaping meta chars
#my $old = '{Test4*4}'; #(iii) using single quotes
my $new = "okay";
s/$old/$new/;
print "$_\n";

It should just demonstrate how to substitute a substring containing
meta chars (e.g. { or *). I had expected that avoiding interpolation
by escaping would help. But even single quote strings aren't better.
Tell me why I am such a fool. would appreciate.

Arne

 

[Sam Holden]

Trying to make a simple replacement of strings I spent some hours
resulting in this:

#!/usr/bin/perl -w
#use strict;

$_ = "Just {Test4*4}";
#my $old = "{Test4*4}"; #(i) normal double quoted match
my $old = "\{Test4\*4\}"; #(ii) escaping meta chars

That doesn't escape anything. { and * are not "special" in
a double quoted string so the backslashes are essentially ignored
(or \{ is converted to { and so on).

#my $old = '{Test4*4}'; #(iii) using single quotes
my $new = "okay";
s/$old/$new/;
print "$_\n";

It should just demonstrate how to substitute a substring containing
meta chars (e.g. { or *). I had expected that avoiding interpolation
by escaping would help. But even single quote strings aren't better.
Tell me why I am such a fool. would appreciate.

perldoc -f quotemeta

or to do things the hard way:

"\\{Test4\\*4\\}"

or

'\{Test4\*4\}'

 

[Arne]

Truth is simple:

perldoc -f quotemeta

is the golden hint. Thank u so much Sam. (was my first posting so that
I cannot back off...)

Arne