The replacement text for find-and-replace operations may contain references to capture-group text from the find. References are of the form $n, where n is the number of the capture group.
Character
Descriptions
$n
The text of capture group n will be substituted for $n. n must be >= 0 and not greater than the number of capture groups. An unescaped $ not followed by a capture group specification is an error.
If you want to specify the $ itself, you need to escape it with backslash like \$.
\
Treat the following character as a literal, suppressing any special meaning. Backslash escaping in substitution text is only required for '$' and '\', but may be used on any other character without bad effects.