Stop Excuting some lines

I have a while loop which goes throw some commands. I want the while loop to execute some of the commands only once while the others should be executed infinitely. I cannot remove these statement outside the loop as they are important in there location. So, is there a way to jump over them after the first execution without disturbing the loop.

Answer 1

[David Young]

flag = 1;
while <condition>
  <commands to be always executed>
  if flag
     <commands to be executed only on first iteration>
  end
  <commands to be always executed>
  if flag
     <commands to be executed only on first iteration>
  end
  < ... >
  flag = 0;
end