title: Keep checking file size and after every 2MB of change execute a command
body: <p>I have video file "test.mp4" which I am downloading using wget. It's more than 100MB+. I want to keep checking the file size and execute certain commands on it after it increments every +2MB or some custom limits. 
  Presently I am trying with nested ifs and while loops:</p>
  
  <pre><code>while true;
  do
      if [[ $(find /home/user/test.mp4 -type f -size +200k 2&gt;/dev/null);
          then
          ##### executre some commands
          while true;
          do
              if [[ $(find /home/user/test.mp4 -type f -size +2000k 2&gt;/dev/null) ]];
                  then
                  ##### executre some commands
                  while true;
                  do
                      if [[ $(find /home/user/test.mp4 -type f -size +4000k 2&gt;/dev/null) ]];
                          then
                          ##### executre some commands
                          while true;
                          do
                              if [[ $(find /home/user/test.mp4 -type f -size +6000k 2&gt;/dev/null) ]];
                                  then
                                  ##### executre some commands
                                  ##### I have to write while loops like this for ever -----------
                                  break;
                              fi
                          done;
                          break;
                      fi
                  done;
                  break;
              fi
          done;
          break;
      fi
  done;
  </code></pre>
  
  <p>But I have to manually do. Is there a way it keeps checking and I can tell some limit and after that it can execute a command?</p>