title: How do I sum together file sizes in bash, grouping together the results by date?
body: <p>On a Linux server that I work with, a process writes randomly-named files at random intervals. Here's a small sample, showing the file size, modification date &amp; time, and file name:</p>
  
  <pre><code>27659   2009-03-09  17:24  APP14452.log
  0       2009-03-09  17:24  vim14436.log
  20      2009-03-09  17:24  jgU14406.log
  15078   2009-03-10  08:06  ySh14450.log
  20      2009-03-10  08:06  VhJ14404.log
  9044    2009-03-10  15:14  EqQ14296.log
  8877    2009-03-10  19:38  Ugp14294.log
  8898    2009-03-11  18:21  yzJ14292.log
  55629   2009-03-11  18:30  ZjX14448.log
  20      2009-03-11  18:31  GwI14402.log
  25955   2009-03-12  19:19  lRx14290.log
  14989   2009-03-12  19:25  oFw14446.log
  20      2009-03-12  19:28  clg14400.log
  </code></pre>
  
  <p>(Note that sometimes the file size can be zero.)</p>
  
  <p>What I would like is a bash script to sum the size of the files, broken down by date, producing output something like this (assuming my arithmetic is correct):</p>
  
  <pre><code>27679 2009-03-09
  33019 2009-03-10
  64527 2009-03-11
  40964 2009-03-12
  </code></pre>
  
  <p>The results would show activity trends over time, and highlight the exceptionally busy days.</p>
  
  <p>In SQL, the operation would be a cinch:</p>
  
  <pre><code>SELECT SUM(filesize), filedate
  FROM files
  GROUP BY filedate;
  </code></pre>
  
  <p>Now, this is all probably pretty easy in Perl or Python, but I'd really prefer a bash shell or awk solution. It seems especially tricky to me to group the files by date in bash (especially if you can't assume a particular date format). Summing the sizes could be done in a loop I suppose, but is there an easier, more elegant, approach?</p>