If you press
ctrl+r in the terminal you will activate the reverse-i-search. With it, you can search your whole history for a command. If you type very long commands you or if you don't remember the whole command that you typed you can just press
ctrl+r and type the bit you remember, the command that matches will show up.
If you want to search it again all you need to do is press
Let's say you used the command
git rebase -i Head~2 before, but you don't remember what does after
git rebase or you just don't feel like typing the whole thing.
ctrl+r and then type
git re if
git rebase -i Head~2 was the last command that you used, it will be shown. Then just press enter to run the command.