Re^4: regex basics

CountZero, did you say !$_ /;\s+/ is invalid syntax?

And here I was all ready to use this on other config files. If fact, I already have:

#!/usr/bin/env perl
use strict;
use warnings;
my $conforig = 'httpd.conf-orig';
my $confnocm = 'httpd.conf-nocomments';
open my $IN,  '<', $conforig
     or die "Could not open $conforig for reading: $!";
my $text;
while (<$IN>) {
  if (!/\#\s+/) {
    $text .= $_;
  }
}
close $IN
   or die "Error closing $conforig: $!";
# remove blank lines
$text =~ s{\n{2,}}{\n}gm;
open my $OUT, '>', $confnocm
     or die "Could not open $confnocm for writing: $!";
print $OUT $text;
close $OUT or die "Error closing $confnocm: $!";
[download]

It seems to work... but please show me the correct negation syntax before the code police smash in my door, drag me off to a detention camp and force me to write JavaScript.

Comment on Re^4: regex basics Download Code

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Re^5: regex basics by choroba (Cardinal) on Feb 02, 2015 at 15:28 UTC
These are not the same: `!$_ /;\s+/ !/\#\s+/` [download] In fact, when you want to mention the thing to be matched, you must use the binding operator: `!( $_ =~ /;\s+/); # or $_ !~ /;\s+/;` [download] Update: Precedence fixed. Thanks AnomalousMonk. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]
Re^6: regex basics by AnomalousMonk (Archbishop) on Feb 02, 2015 at 19:13 UTC
`! $_ =~ /;\s+/;` Because of the high precedence of the `!` (logical-not) operator versus `=~` (see perlop), the regex actually matches against either `''` (the empty string) or '1'. `c:\@Work\Perl>perl -wMstrict -MO=Deparse,-p -le "! $_ =~ /;\s+/; " BEGIN { $^W = 1; } BEGIN { $/ = "\n"; $\ = "\n"; } use strict 'refs'; ((!$_) =~ /;\s+/); -e syntax OK` [download] These are equivalent: `! ($_ =~ /;\s+/); # or $_ !~ /;\s+/;` [download] Give a man a fish: `<%-(-(-(-<`	[reply] [d/l] [select]
Re^6: regex basics by Anonymous Monk on Feb 04, 2015 at 07:18 UTC
Understood. =~ means match and !~ means no match. This should work: `#!/usr/bin/env perl use strict; use warnings; my $iniprod = 'php.ini-production'; my $ininocm = 'php.ini-nocomments'; open my $IN, '<', $iniprod or die "Could not open $iniprod for reading: $!"; my $text; while (<$IN>) { if ($_ !~ /;\s+/) { $text .= $_; } } close $IN or die "Error closing $iniprod: $!"; # remove blank lines $text =~ s{\n{2,}}{\n}gm; open my $OUT, '>', $ininocm or die "Could not open $ininocm for writing: $!"; print $OUT $text; close $OUT or die "Error closing $ininocm: $!";` [download]	[reply] [d/l]