Insert text literally when you replace

How to do it

In a replacement string, $&, $1 or \1 mean "the matched text" or "group 1". Content that happens to contain them comes out mangled. Pass a callback that returns the text, or use the language's quoting helper. A plain substring replace without patterns is also safe.

Example

// JavaScript: $&, $1 and $' are special in a replacement string
page.replace('<!--body-->', html);        // Bad
page.replace('<!--body-->', () => html);  // Good: a function is inserted as is

# Python: \1 and \g<0> are special in re.sub's replacement string
re.sub(r"<!--body-->", html, page)            # Bad
re.sub(r"<!--body-->", lambda m: html, page)  # Good

// PHP: $1 and \1 are special in preg_replace's replacement
preg_replace('/<!--body-->/', $html, $page);                          // Bad
preg_replace_callback('/<!--body-->/', fn($m) => $html, $page);       // Good

// Java: $ and \ are special in replaceAll's replacement
page.replaceAll("<!--body-->", html);                            // Bad
page.replaceAll("<!--body-->", Matcher.quoteReplacement(html));  // Good

How to check

Insert the text $& $1 \1 $' through every template or replace step. The output contains those characters unchanged.