title: r does not show specified dates on x-axis
body: <p>I used the following to generate a histogram</p>
  
  <pre><code>mi= 1425168014.519
  ma= 1427919527.540
  b=mi+rnorm(2000,sd=1)*(ma-mi)
  hist(as.POSIXct(b, origin="1970-01-01"),breaks=50, freq = TRUE,axes=F)
  axis.POSIXct(1, at=seq(as.Date("2015-01-01"), as.Date("2015-04-01"), by="1 days"), format="%d %b %y")
  </code></pre>
  
  <p>But the specified dates are not shown in entirety. It only shows as minor ticks. I want it to be shown as labels.</p>