1      Once a "command" has been invoked, you can interrupt its operation by
 2 pressing the BREAK key.  After the command has stopped, Multics returns to
 3 "command level."  But this is command level 2.
 4 
 5      While you are at this level, you can resume operation of the command by
 6 issuing the start command.  You can also use the
 7 program_interrupt (pi for short) command when you interrupt operation of certain
 8 editors, like emacs, qedx, and ted, or programs that interact with you by
 9 asking you to supply information as you go.  If by chance you use
10 program_interrupt with a command that cannot be restarted by it, a message to
11 that effect will be printed.
12 
13      This command, unlike start, accomplishes what you probably want when you
14 press BREAK: it aborts the most recent action and returns to the previous
15 level.
16 
17      If you do not wish to restart the command you interrupted, you should
18 issue the release command before issuing any other commands.  That will
19 return you to level 1, the regular command level.