...
Other characters can be inserted literally , although (some text editors are better at this than others), or consider using chr() and converting the string to a regular expression.
Rationale
KRL uses the hash character to delimit regular expressions instead of the more common (and acceptable) slash (/) because the slash is a frequently used character in URL paths. This removes the need to quote the slash with backslashes: re/\/archives\/\d{4}\//. Using an alternate delimiter makes the regex more readable and thus communicates its meaning more clearly.
...