)*900,
 start time == end time - 1hour,
 resolution == 900.</pre>
<p>Using the bash shell, this could look be:</p>
<pre>
 TIME=$(date +%s)
 RRDRES=900
 rrdtool fetch subdata.rrd AVERAGE -r $RRDRES \
    -e $(($TIME/$RRDRES*$RRDRES)) -s e-1h</pre>
<p>Or in Perl:</p>
<pre>
 perl -e '$ctime = time; $rrdres = 900; \
          system &quot;rrdtool fetch subdata.rrd AVERAGE \
                  -r $rrdres -e @{[int($ctime/$rrdres)*$rrdres]} -s e-1h&quot;'</pre>
<p>
</p>
<h2><a name="at_style_time_specification">AT