title: How do I calculate the mean of a column
body: <p>Anyone know how can I calculate the mean of one these columns (on linux)?? </p>
  
  <pre><code>sda               2.91    20.44    6.13    2.95   217.53   186.67    44.55     0.84   92.97
  sda               0.00     0.00    2.00    0.00    80.00     0.00    40.00     0.22  110.00 
  sda               0.00     0.00    2.00    0.00   144.00     0.00    72.00     0.71  100.00 
  sda               0.00    64.00    0.00    1.00     0.00     8.00     8.00     2.63   10.00
  sda               0.00     1.84    0.31    1.38    22.09   104.29    74.91     3.39 2291.82 
  sda               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00  
  </code></pre>
  
  <p>For example: mean(column 2)</p>