11.8 Repeating a Cycle of Commands

The !! history substitution gives a copy of the previous command. Most people use it to re-execute the previous command line. Sometimes I want to repeat a cycle of two commands, one after the other. To do that, I just type !-2 (second-previous command) over and over:

% vi plot
   ...
% vtroff -w plot
   ...
% !-2
vi plot
   ...
% !-2
vtroff -w plot
   ...

You can cycle through three commands with !-3, four commands with !-4, and so on. The best part is that if you can count, you never have to remember what to do next. :-)