title: Gnu time and formatting output
body: <p>I wanted to use gnu time to measure running time of some little .c programs. In the man it is written that:</p>
  
  <pre><code>-f FORMAT, --format FORMAT
  Use FORMAT as the format string that controls the output of time.  See the below more information.
  </code></pre>
  
  <p>Then in examples we have:</p>
  
  <pre><code>To run the command `ls -Fs' and show just the user, system, and total time:
  time -f "%E real,%U user,%S sys" ls -Fs
  </code></pre>
  
  <p>But when I try to issue this command from example i get:</p>
  
  <pre><code>time -f '%E real,%U user,%S sys' ls -Fs
  -f: command not found
  
  real    0m0.134s
  user    0m0.084s
  sys     0m0.044s
  </code></pre>
  
  <p>I am wondering where is the problem, where am I making a mistake? I just want to show the user time, that is why I am toying with time output format.</p>