Why doesnt [\n$] work while (\n|$) does?

Question

We have this string (without new line at the end):

The quick brown fox jumps over the lazy dog

I want to match the entire string until new line \n or end $ occurs.

• I firstly tried: [\n$] - didnt work.
• Then i tried (\n|$) - did work

Question: Why doesnt [\n$] match the string while (\n|$) does?

Answer 1

Because $ in a character class is seen as a literal

Answer 2

Another way to look at it: a character class matches exactly one character. The end-of-line matched by $ is an empty string. That's why and end-of-line cannot be matched by a character class.

(As a consequence, the only possible interpretation for $ is the literal.)