PHP requires escaping quotes and literal backslashes (i.e., backslashes not used for metacharacters or escaping other characters). For many cases, it doesn't af

PHP requires escaping quotes and literal backslashes (i.e., backslashes not used for metacharacters or escaping other characters). For many cases, it doesn't affect anything, but it can turn into a bit of a nightmare if you're matching anything involving backslashes since you need four backslashes to match one literal backslash. Perl's regular expression literals are also nicer for things like splitting a long expression over multiple lines.