Is there a way to define a bash readline command?

Question

I can not find a way to do that from bash. So Is there a way to define a bash readline shortcut that will insert a dynamically generated string at the position of the cursor?

E.g., I want to insert date:

bind '"\C-xx": my-dynamical-date'

aaa  bbb
--------
    ^ cursor is here

# After pressing "\C-xx":

aaa Sun Apr 22 22:19:00 CST 2018 bbb
------------------------------------
                                ^ cursor is here

So how to define my-dynamical-date readline command?

Do what, exactly? Please [edit] your question and explain what you are trying to do. — terdon, Apr 22 '18 at 13:48
You can redefine a keybinding, for example bind '"^M":"\nmy-alias\n"' — Arkadiusz Drabczyk, Apr 22 '18 at 13:50
I edited to explain what I think you want to do. Please correct it if I'm wrong. — terdon, Apr 22 '18 at 14:53
Possible duplicate of Can bash write to its own input stream? — Chris Davies, Apr 22 '18 at 19:37
Possible duplicate of Put text in the bash command line buffer — Chris Davies, Apr 22 '18 at 19:38

Arkadiusz Drabczyk · Accepted Answer · 2018-04-22T16:17:13.750

9

A bit silly but it could be something like this:

bind '"\C-xx":"$(date) \e\C-e\ef\ef\ef\ef\ef"'

It first enters a literal $(date), then calls shell-expand-line and then moves 5 words forward.

To save the keybinding, add the following to inputrc:

"\C-xx":"$(date) \e\C-e\ef\ef\ef\ef\ef"

edited Apr 22 '18 at 16:17

answered Apr 22 '18 at 15:59

Arkadiusz Drabczyk

25,539

Nice! Any idea how to do this in .inputrc? I tried but couldn't figure out how to have a command substitution ($(command)) be expanded from the .inputrc file. – terdon Apr 22 '18 at 16:03
@terdon: I've just the added the line above to my ~/.inputrc and run bind -f .inputrc. I pressed C-x x a couple of times and a current time was displayed each time. – Arkadiusz Drabczyk Apr 22 '18 at 16:18
1

shell-expand-line can be used like this! It's great! – Big Shield Apr 22 '18 at 16:18
1

@ArkadiuszDrabczyk ah! I hadn't noticed the \e\C-e for shell-expand-line! That's what I was missing. Thanks! – terdon Apr 22 '18 at 16:20
The only solution to get that in .inputrc. Could you make shell-expand-line work in ipython, python or perl REPL ? – Tinmarino Mar 31 '19 at 16:30

score 4 · Answer 2 · answered Apr 22 '18 at 18:00

You can write a function that edits the readline variables READLINE_POINT and READLINE_LINE. For example, set in your .bashrc:

_myinsert() { # add date at point
    local TOADD=$(date)
    READLINE_LINE="${READLINE_LINE:0:$READLINE_POINT}${TOADD}${READLINE_LINE:$READLINE_POINT}"
    READLINE_POINT=$(($READLINE_POINT + ${#TOADD}))
}
# cannot put this in ~/.inputrc
bind -x '"\C-xx":_myinsert'

This uses the -x option of bind to call your function. I don't know of any way to put the equivalent in a ~/.inputrc file. (You certainly cannot just begin the line with -x, for example).

Is there a way to define a bash readline command?

2 Answers2

Linked