Re: Why does grep add /dev/null the first time?

[Eli Zaretskii]

> Date: Thu, 14 Aug 2014 11:12:07 -0700 (PDT)
> From: guido@dropbox.com
> 
> The (minor) issue with this is that the first time after starting Emacs (and 
> only the first time) the shell command actually executed has "/dev/null" 
> appended (causing the search to return no results). Any subsequent 
> invocations it will work fine.
> 
> What am I missing?

See the doc string of grep-use-null-device, which explains that.  Its
default value is 'auto-detect', which causes Emacs to invoke Grep once
for the purposes of detecting how to invoke it thereafter.