Add this to you inputrc:
"\e[A": history-search-backward
"\e[B": history-search-forward
Now up and down arrows will search your history with whatever you already have typed at the prompt. Re-running a command often? Probably just have to type its first letter and hit up arrow once or twice.
(fyi, for others: you need not use ctrl-r, just type and press up and down)
Add this to you inputrc:
"\e[A": history-search-backward
"\e[B": history-search-forward
Now up and down arrows will search your history with whatever you already have typed at the prompt. Re-running a command often? Probably just have to type its first letter and hit up arrow once or twice.