there are many ways i do it, depending on the situation...

1. pick a seperator that won't appear in your text, like \0. set $/ to this value when parsing the config file
2. use perl's heredoc syntax, and do the file
3. use one of the fine Config modules from CPAN
4. RECOMMENDED use my favourite config module, YAML.

~Particle *accelerates*

The problem is that \n is not a variable, you can't interpolate it, it is a meta character that the print, etc. understand. When you read in your key/value pair of TEXT=Hello\nWorld\n! you are reading in a literal "\" and a literal "n", not the metacharacter "\n". Once it is read in as "\" and "n", no amount of interpolation will make it a meta character. For all intents and purposes, you can look at your input text as: "Hello\\nWorld\\n!".

You were on the right track with your substition.

HTH

I'm not sure if i understand what you mean.

If you want the literal newlines to be printed try something like this

perl -we 'print qw/Hello\nWorld\n!/'
Hello\nWorld\n!
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# perl -we 'print "Hello\nWorld\n!"'
Hello
World
!
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In its infinite wisdom, the Camel Book says:

You may only interpolate expressions that begin with $ or @, because those are the two characters (along with backslash) that the string parser looks for.(p. 62)

Interpolation is extremely powerful but strictly controlled in Perl. It happens only inside double quotes, and in certain other "double-quotish" operations(p. 63)

CountZero

"If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law

#!/usr/bin/perl

use strict;
use warnings;

my $line = 'TEXT=Hello\nWorld!\n'; # No interpolation
$line =~ s/^TEXT=//g;
print "$line\n";
my $interpolated = eval "qq{$line}";
print $interpolated;
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Hello\nWorld!\n
Hello
World!
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Arjen

Uh...

Just a note that this can be a little dangerous. In the worst case, the eval will mess up. But if someone just wants to mess with you, they can do a very nice job of it. Observe:



my $line = 'TEXT=};print `ps`;print "Your machine is h4x0r3d!!$/";qq{H
+ello\nWorld!\n';
..

OUTPUT:
  PID  TT  STAT      TIME COMMAND
 5808  p0  S      0:00.02 _su (csh)
 5816  p0  S+     0:00.01 perl mylittleprogram.pl
 5817  p0  R+     0:00.00 ps
  149  v0  IWs+   0:00.00 /usr/libexec/getty Pc ttyv0
Your machine is h4x0red!!
Hello
World
#
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I'm just showing that this can be a little dangerous but if you're the only one who is writing to the config file, you'll need to make certain you never use } or you'll most likely get $interpolated = undef. Of course, a prankster could put some code in the config file as I just showed and have it do a lot of nifty things and you still get the output you expected. So it could be some time before you'd realize anything is wrong at all. Of course, what are the chances of that? ;-)

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1

I know ;-) But the previous posts basically asserted that without some substitution, it wasn't possible to do this. When using this technique, you'll want to turn on taint checking and thus be forced to inspect the input (the TEXT=... in this case). But while doing that, it's probably easier to make the substitution right away, thereby removing the need for the eval altogether!

Sometimes, using this technique (or the do EXPR function) is useful for writing a script which uses a configuration file without using a special module for it. It's just another way of doing something, and can be very convenient sometimes.

Arjen