How to repeat currently typed in parameter on bash console?

Question

I was just typing something along the lines of:

mv foo/bar/poit/zoid/narf.txt

and suddenly realized, damn, I have to type large parts of that parameter again

mv foo/bar/poit/zoid/narf.txt foo/bar/poit/zoid/troz.txt

Even with tabcompletion, quite a pain. I know I can copy paste the parameter by mouse-selecting the text and middleclick but that is not good enough. I want to remain on the keyboard.

So is there a way to copy paste the current parameter of the line using the keyboard?

Answer 1

If I've planned ahead, I use brace expansion. Here is another approach using the default readline keyboard shortcuts:

• mv foo/bar/poit/soid/narf.txt: start
• Ctrl-w: unix-word-rubout to delete foo/bar/poit/soid/narf.txt
• Ctrl-ySpaceCtrl-y: yank, space, yank again to get mv foo/bar/poit/soid/narf.txt foo/bar/poit/soid/narf.txt
• Meta-backspaceMeta-backspace: backward-kill-word twice to delete the last narf.txt
• troz.txt: type the tail part that is different

If you spend any non-trivial amount of time using the bash shell, I'd recommend periodically reading through a list of the default shortcuts and picking out a few that seem useful to learn and incorporate into your routine. Chapter 8 of the bash manual is a good place to start. Knowing the shortcuts can really raise your efficiency.

Answer 2

As in your example, you can use next construction:

mv foo/bar/poit/zoid/{narf.txt,troz.txt}

or even (as suggested Ansgar Esztermann):

mv foo/bar/poit/zoid/{narf,troz}.txt

instead ot typing/copypasting long address twice.

Answer 3

Playing around I got this to work:

mv foo/bar/poit/zoid/narf.txt

Hit Enter
to store the last parameter.

Now use ↑ to get last typed in line back. Enter a space and to get the last used parameter use:

Alt + .

I hate provoking an error, but it gets the job done in this use case.