title: What does TTY mean in the unix ps command?
body: <p>When I run PS one of the columns output is TTY.  What does this mean?  In particular, how does as value of "??" compare with "ttys000"?</p>
  
  <p>I ask because I have a Java program execute <code>sort</code> via ProcessBuilder, and when this program is run via my IDE (IntelliJ) the process takes 5x less than when run as an executable jar outside the IDE.  </p>
  
  <p>In each case I run ps when the sort is running and the only difference is the IDE creats a process with a TTY of ?? whereas the jar creates a process with TTY of ttys000.    </p>