Regular Expressions Anchor Characters: Dollar ($)
Remarks[edit | edit source]
A great deal of regex engines use a "multi-line" mode in order to search several lines in a file independently.
Therefore when using
$, these engines will match all lines' endings. However, engines that do not use this kind of multi-line mode will only match the last position of the string provided for the search.
Match a letter at the end of a line or string[edit | edit source]
The above matches one letter (the letter
g) at the end of a string in most regex engines (not in Oniguruma, where the
$ anchor matches the end of a line by default, and the
m (MULTILINE) modifier is used to make a
. match any characters including line break characters, as a DOTALL modifier in most other NFA regex flavors). The
$ anchor will match the first occurrence of a
g letter before the end of the following strings:
In the following sentences, only the letters in bold match:
Anchors are characters that, in fact, do not match any character in a string
Their goal is to match a specific position in that string.
Bob was helping
But his edit introduced examples that were not matching!
In most regular expression flavors, the
$ anchor can also match before a newline character or line break character (sequence), in a MULTILINE mode, where
$ matches at the end of every line instead of only at the end of a string. For example, using
g$ as our regex again, in multiline mode, the italicised characters in the following string would match:
tvxlt obofh necpu riist g\n aelxk zlhdx lyogu vcbke pzyay wtsea wbrju jztg\n drosf ywhed bykie lqmzg wgyhc lg\n qewrx ozrvm jwenx