title: Keeping track of history of commands of multiple sessions of ksh
body: <p>I am using multiple sessions of ksh on a linux machine. On one terminal when I do history, I only see history of commands typed on that terminal. 
  When I log out all sessions, I want to make sure that history of commands typed on all the terminal get appended on one file say .bash_history. Is it possible?</p>
  
  <p>Even when I don't log out, are all these commands dynamically get appended to this history file?</p>
  
  <p>I am wary of losing my commands like when someone helps me do something, I want to make sure that I can refer to that command later on.</p>
  
  <p>How do I set the size of .bash_history file</p>
  
  <p>Thanks,</p>