t>
<dd><p>When resetting the global environment is overkill, there is the <code>convert</code>
command, which allows one time conversions.  It can accept either a single
argument or a list of units to use in conversion.  When a convert operation is
done, the normal global evaluation system is bypassed, in order to avoid the
desired result being converted again.  As a consequence, for inexact
calculations &quot;rat&quot; warnings will be visible if the global environment
controlling this behavior (<code>ratp