Navigating Bash History with Ctrl+R
I spend a lot of time at command line, and bash records the history of all the commands I've typed and puts it in .bash_history (there's a limit on how many it stores but for me it goes back a few days). I find it really useful to look back at the history to use the same commands again or edit them slightly. You can press the up arrow to go through your history but it can take a really long time to find what you're looking for. So instead, try Ctrl + r.
To do this: first press Ctrl + r, then start typing the command or any part of the command that you are looking for. You'll see an autocomplete of a past command at your prompt. If you keep typing, you'll get more specific options appear. You can also press Ctrl + r again as many times as you want to, this goes back in your history to the previous matching command each time.
Once you see a command you like, you can either run it by pressing return, or start editing it by pressing arrows or other movement keys. I find this a really useful trick for going back to a command I know I used recently, but which I can't remember or don't want to look up again. I hope this is a useful trick for you too!

Thanks Lorna, i tried it and it works great. I normally use the command history | grep "" but this is faster i think.
Lineke: I like this approach because it all happens at the prompt and when you get the right command, it's ready to be run. Glad you liked it!
very useful ,Thanks.~
Thanks, this is very useful! I realise that I've wasted a lot of time using "history | grep" :(