[PATCH] ash: add support for history buffer

[Ralf Friedl]

Dennis Groenen wrote:
> Ash writes to ~/.ash_history after every command, causing excessive
> wear on devices which use a flash-based device as their storage medium
> (i.e. one erase block cycle per command).
> This patch allows you to set a temporary location where ash's history
> will be saved until the shell is exited.
By the way, bash doesn't write the history after every command, just on 
exit from the shell.

Ralf