Setting auto-mode-alist in emacs

Question

I notice that the current auto-mode-alist entries all end with a single quote, for example

 ("\\.java\\'" . java-mode)

What is the purpose of the single quote. I would have expected to see

 ("\\.java$" . java-mode)

The reason I ask is that I am trying to get files with names matching regexp

^twiki\.corp.* 

to open in org-mode. I have tried the following without success:

(add-to-list 'auto-mode-alist '("^twiki\\.corp" . org-mode))
(add-to-list 'auto-mode-alist '("\\'twiki\\.corp" . org-mode))

The following works:

(add-to-list 'auto-mode-alist '("twiki\\.corp" . org-mode))

but is not quite what I want since file names with twiki.corp embedded in them will be opened in org-mode.

Answer 1

\\' matches the empty string at the end of the string/buffer:

http://www.gnu.org/software/emacs/manual/html_node/emacs/Regexp-Backslash.html e l

$ will match the end of the line: If you have newlines in your filename (very uncommon) $ will match the newline and not the end of the string.

The regex is matched against the whole filename, so you need include "/" to match the directory seperator:

(add-to-list 'auto-mode-alist '("/twiki\\.corp" . org-mode))