<p>Every time I use the "at" command, I get this message:</p>

<pre><code>warning: commands will be executed using /bin/sh
</code></pre>

<p>What is it trying to warn me about? More importantly, how do I turn the warning off?</p>

It serves as a good warning to those of us that don't use bash as our shell, because we we'll forget that a feature that's in our day-to-day shell isn't going to be available when this code is run at the appointed time.
i.e.
```
```
username@hostname$ at 23:00     
warning: commands will be executed using /bin/sh
at> rm **/*.pyc
at> <EOT>
job 1 at 2008-10-08 23:00
```
```
The use of '**' there is perfectly valid zsh, but not /sbin/sh! It's easy to make these mistakes if you're used to using a different shell, and it's your responsibility to remember to do the right thing.