bash - first argument of the previous command

Question

Hi

I know that ESC DOT gives you the last argument of the last command.

But I'm interested in first argument of the last command. Is there a key binding to do so?

On the same lines, is there a generic way of getting nth argument from last command. (I know that in a bash script you can use $0, $1 etc., but these don't work on commandline)

Also, what about iterating through 0th argument of previous commands, like we can do with last argument by continuing pressing ESC DOT

Answer 1

!^ may be the command for the first argument. i'm not sure if there is a way to get the nth.

Answer 2

Use !:n to get the n'th word from the previous command line. !:0 is the command, the arguments start at index 1. See also this article on history expansion.

$ ls -l /
...
$ echo !:1
-l

Answer 3

Just as M-. (meta-dot or esc-dot or alt-dot) is the readline function yank-last-arg, M-C-y (meta-control-y or esc-ctrl-y or ctrl-alt-y) is the readline function yank-nth-arg. Without specifying n, it yanks the first argument of the previous command.

To specify an argument, press Escape and a number or hold Alt and press a number. You can do Alt-minus to begin specifying a negative number then release Alt and press the digit (this will count from the end of the list of arguments.

Example:

Enter the following command

$ echo a b c d e f g
a b c d e f g

Now at the next prompt, type echo (with a following space), then

Press Alt-Ctrl-y and you'll now see:

$ echo a

without pressing Enter yet, do the following

Press Alt-3 Alt-Ctrl-y

Press Alt-- 2 Alt-Ctrl-y

Now you will see:

$ echo ace

By the way, you could have put the echo on the line by selecting argument 0:

Press Alt-0 Alt-Ctrl-y

Edit:

To answer the question you added to your original:

You can press Alt-0 then repeatedly press Alt-. to step through the previous commands (arg 0). Similarly Alt-- then repeating Alt-. would allow you to step through the previous next-to-last arguments.

If there is no appropriate argument on a particular line in history, the bell will be rung.

If there is a particular combination you use frequently, you can define a macro so one keystroke will perform it. This example will recall the second argument from previous commands by pressing Alt-Shift-Y. You could choose any available keystroke you prefer instead of this one. You can press it repeatedly to step through previous ones.

To try it out, enter the macro at a Bash prompt:

bind '"\eY": "\e2\e."'

To make it persistent, add this line to your ~/.inputrc file:

"\eY": "\e2\e."

Unfortunately, this doesn't seem to work for arg 0 or negative argument numbers.