I found a command a couple of months ago that made my bash history auto-complete on what\'s already on the line when pressing the up arrow:
$ vim fi
Probably something like
# ~/.inputrc "\e[A": history-search-backward "\e[B": history-search-forward
or equivalently,
# ~/.bashrc
if [[ $- == *i* ]]
then
bind '"\e[A": history-search-backward'
bind '"\e[B": history-search-forward'
fi
(the if statement checks for interactive mode)
Normally, Up and Down are bound to the Readline functions previous-history and next-history respectively. I prefer to bind PgUp/PgDn to these functions, instead of displacing the normal operation of Up/Down.
# ~/.inputrc "\e[5~": history-search-backward "\e[6~": history-search-forward
After you modify ~/.inputrc, restart your shell or use Ctrl+X, Ctrl+R to tell it to re-read ~/.inputrc.
By the way, if you're looking for relevant documentation:
Bash uses The GNU Readline Library for the shell prompt and history.