The Korn shell has the ability to utilize vi editor commands to edit commands in your history. If you are familiar with the vi editor, you will love this feature.
To enable vi editing, type the following command, or place it in your .kshrc file:
set -o vi
Then you can use vi commands. Press escape to enter vi command mode, and then you have access to many vi commands. For example, k will move up through previous commands in the history, /tail will search for the most recent command containing the word tail and pressing n will find the next occurence of that search term.
Once you have found a command that you want to repeat, just press ENTER, and it will be run again. You can edit the command with R to replace characters from your current position, x to delete the current character, i to insert characters before the current character, a append characters after the current character, and $ to move to the end of the command.