What does the two symbols (^ and $) stand for in Nginx configuration?

Question

Can anybody help understand why there is ^ and $? I known ^ means "start with", $ means "end with". I just don't know why we need that? Could you please list some URIs that match the following rewrite and show me the difference with or without the two symbols?

rewrite ^/users/(.*)$ /show?user=$1? last;

Duplicate of http://stackoverflow.com/questions/22937618/reference-what-does-this-regex-mean — Unihedron, Sep 24 '14 at 12:21
Read the answer on the linked question, particularly on "Anchors" section. — Andrew T., Sep 24 '14 at 12:27
I know exactly what the ^ and $ mean, I just need example to clarify them, that link is not clear for me my confusion. but still thanks. — Vidy Videni, Sep 25 '14 at 02:08

score 4 · Accepted Answer · answered Sep 24 '14 at 12:43

These are present to ensure that the entire URL is matched when performing the rewrite.

For example, without the ^, these URLs would match:

/admin/users/foo
/whatever/users/bar

In this case, the $ isn't really required because the * is greedy (. matches anything and the * matches as much as possible). This results in the expression matching the remaining input even without the $. In a more restricted case such as:

rewrite ^/users/dan$ /show?user=dan last;

The $ is important for the same reason. Without it, these URLs would match:

/users/dan/delete
/users/dan/profile
/users/danny

But with it, only the exact url /users/dan would match.

the reason why the ^/users/(.*)$ makes me confused is I think every request URI starts with /, now I understand ^/users means " a request URI starts with the whole part "/users" " , another reason is I don't know why it still adds $, I also think it is not necessary in this context, You have solved my years confusion. thanks. — Vidy Videni, Sep 25 '14 at 02:14

What does the two symbols (^ and $) stand for in Nginx configuration?

1 Answers1