This s/(<url>)|<|>/$1||''/eg and this $_[0] =~ s/<|>//g will replace the "<" and ">", but what I am trying to do is to replace "<" and ">" only if this pattern "<url>" is not found on the string. At the end the string should be:
From this: "This is not ok < but this is ok <url>".
To: "This is not ok but this is ok <url>".