How to use arguments from previous command?
I know that Esc + . 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 the nth argument from the last command?
I know that in a bash script, you can use $0
, $1
etc., but these don't work on the commandline.
Also, what about iterating through the 0th argument of previous commands, like we can do with the last argument by continuously pressing Esc + .?
!$
gets the last element of the previous command line argument.
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--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.
To use the first argument, you can use !^
or !:1
Example:
$ echo a b c d e
a b c d e
$ echo !^
echo a
a
$ echo a b c d e
a b c d e
$ echo !:1
echo a
a
Since your question is about using any other arguments, here are some useful ones:
!^ first argument
!$ last argument
!* all arguments
!:2 second argument
!:2-3 second to third arguments
!:2-$ second to last arguments
!:2* second to last arguments
!:2- second to next to last arguments
!:0 the command
!! repeat the previous line
The first four forms are more often used. The form !:2-
is somewhat counter-intuitive, as it doesn't include the last argument.
I liked @larsmans answer so much I had to learn more. Adding this answer to help others find the man page section and know what to google for:
$ man -P 'less -p ^HISTORY\ EXPANSION' bash
<...>
Word Designators
Word designators are used to select desired words from the event.
A : separates the event specification from the word designator.
It may be omitted if the word designator begins with a ^, $, *, -,
or %. Words are numbered from the beginning of the line, with the
first word being denoted by 0 (zero). Words are inserted into the
current line separated by single spaces.
0 (zero)
The zeroth word. For the shell, this is the command word.
n The nth word.
^ The first argument. That is, word 1.
$ The last argument.
% The word matched by the most recent ‘?string?’ search.
x-y A range of words; ‘-y’ abbreviates ‘0-y’.
* All of the words but the zeroth.
This is a synonym for ‘1-$’.
It is not an error to use * if there is just one word in
the event; the empty string is returned in that case.
x* Abbreviates x-$.
x- Abbreviates x-$ like x*, but omits the last word.
If a word designator is supplied without an event
specification, the previous command is used as the event.
!^ may be the command for the first argument. i'm not sure if there is a way to get the nth.