Not to be rude - but exim does have some very well written
documentation.. The file spec.txt, included with the distribution
tarball explains every option you can put in the config file.
Here is an excerpt below from the explanation for require_files:
Sometimes "stat()" yields the error EACCES ('Permission denied'). This
means that the user is not permitted to read one of the directories on
the file's path. The default action is to consider this a configuration
error, and delivery is deferred because the existence or non-existence
of the file cannot be determined. However, in some circumstances it may
be desirable to treat this condition as if the file did not exist. If
the file name (or the exclamation mark that precedes the file name for
non- existence) is preceded by a plus sign, then the EACCES error is
treated as if the file did not exist. For example:
require_files = +/some/file
This option provides a general mechanism for predicating the running of
a director or router on the existence or non-existence of certain files
or directories. A failure to expand the string, or the presence of a
path within it that is not fully qualified causes a panic error. This
includes forced failure, because the whole string is expanded once,
before being interpreted as a list. If you want a particular variant of
the expansion to specify that no files are to be checked, you should
cause it to yield an empty string rather than forcing failure.
On Mon, 12 Nov 2001, Marc Perkel wrote:
> OK - similar question - what does the "+" plus sign do?
>
> "Dave C." wrote:
>
> > On Mon, 12 Nov 2001, Tamas TEVESZ wrote:
> >
> > > On Mon, 12 Nov 2001, Dave C. wrote:
> > >
> > > > require_files = ${local_part}:+${home}/.procmailrc
> > >
> > > could someone please tell me what "require_files = ${local_part}" is
> > > good for ? i've been killing this from my setups as i find no meaning
> > > for it..
> >
> > You mean the entire line, or just the ${local_part}:+ section?
> >
> > The line is there to ensure this directory only runs if the user does in
> > fact have a .procmailrc file..
> >
> > The ${local_part}:+ section tells exim to setuid to that user before
> > checking, in case the users homedir is not world readable
> >
> > --
> >
> > ## List details at http://www.exim.org/mailman/listinfo/exim-users Exim details at http://www.exim.org/ ##
>
>
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