Perhaps the following, which uses a negative lookhead and a negative lookbehind, will be helpful:

use strict;
use warnings;

my $test = "this is not OK < but this is ok <url>";
print rep($test);

sub rep {
    $_[0] or return $_[0];
    $_[0] =~ s/<(?!url)|(?<!url)>//g;
    return $_[0];
}

[download]

Output:

this is not OK  but this is ok <url>

[download]

Your sub returns '' if $_[0] evaluates to false. This means that 0 and !defined $_[0] would convert to '', and perhaps that's your intent. In these cases, the above just returns what was sent (if anything), so you may need to adjust it.

In reply to Re: Hazardous characters filter by Kenosis
in thread Hazardous characters filter by Anonymous Monk

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