On macOS when using fish shell, you can launch whatever is bound as your EDITOR command with whatever you have typed as your current command by triggering MetaE. If you have set your editor to use Option⎇ as Meta (and you should!) this means you just have to hit ⎇E to edit the current command before sending it.

This works in both Terminal and iTerm2, and I assume other editors as well but I have not tested it. I think this is a fish-ism, because it does not work in bash or zsh on my machine.

One of the big places I end up doing this is when writing a commit message: I might start thinking it is a one-liner, and then realize I want to add some context, and don’t want to think about manual line-wrapping to match the usual commit message guidelines. So I’ll just hit ⎇E to pop up BBEdit, edit it there, using its handy line-wrapping tools, and then save and close it. That drops me back into the terminal with whatever edits I have made.

This will use whatever you have $EDITOR set to, and it’s probably important to use whatever the “wait to return” flag is for your editor of choice — usually -/--wait.

Also handy when you realize you want to build up a multiline command with \s separating each line and are concerned about accidentally hitting Return ⤶ along the way!