Re: regexp NOT matching an extension

[Gareth Rees]

Leo wrote:
> In dired-omit-files I need a regexp matching all files without the
> extension '.pem'.

You need this regexp:

    [^m]$\|[^e]m$\|[^p]em$\|[^.]pem$

Your regexp [^m]$ appears to work because it's the first alternative
that catches most of the files you want to exclude: only files ending in
'm' go on to be considered by the other three cases.

-- 
Gareth Rees