#! perl
use strict;
use warnings;

my %patterns =
(
    original_text => "\<\?php\ \@error_reporting\(0\)\;\ if\ \(\!isset\(\$eva1fYlbakBcVSir\)\)\ \{\$eva1fYlbakBcVSir\ \=\ \"7kyJ",
    double_quoted => "<?php \@error_reporting(0); if (!isset(\$eva1fYlbakBcVSir)) {\$eva1fYlbakBcVSir = \"7kyJ",
    single_quoted => '<?php @error_reporting(0); if (!isset($eva1fYlbakBcVSir)) {$eva1fYlbakBcVSir = "7kyJ',
);

for (qw[original_text double_quoted single_quoted])
{
    my $text = $patterns{$_};
    my $re   = qr[^\Q$text\E];
    print "\n", $_, ': ', "\n", $text, " -->\n", $re, "\n";
}