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I want to be able to change a global keybinding by calling an Emacs function.

The command in question is:

gsettings set org.gnome.desktop.wm.keybindings switch-applications "['<Super>Tab']"

This Linux shell command sets the keybinding for changing between applications.

When I call shell-command within Emacs and enter the above command, the expected result always happens: application switching becomes bound to Super-Tab.

The correct form for a simple shell-command is (shell-command "command"). I have successfully tested that this works by evaluating (shell-command "ls").

However, when I evaluate the function

(shell-command "gsettings set org.gnome.desktop.wm.keybindings switch-applications "['<Super>Tab']"")

instead of this working as it does when I offer this string directly to shell-command prompt, I receive the error message: eval-region: Invalid read syntax: "]".

I have tried every syntactic variation of this command that I can think of and read threads and blog posts discussing simple uses of shell-command, but I have found nothing applicable to this problem.

I would be grateful for any advice.

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  • 1
    Just checking, but are you backslashing the double quotes? As in (shell-command "gsettings set org.gnome.desktop.wm.keybindings switch-applications \"['<Super>Tab']\"")? Otherwise the string representing your command is ending prematurely at the first double quotes.
    – kozina-adjacent
    Commented Feb 28, 2023 at 17:06
  • @kozina-adjacent: please make your comment into an answer. It is without a doubt the correct answer.
    – NickD
    Commented Feb 28, 2023 at 17:31

1 Answer 1

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When including double-quotes inside a string, be sure to "escape" them, which in Emacs is accomplished with a backslash, otherwise the string representing your command will end prematurely. (Well, at least earlier than you probably intended it to.) See String syntax in the Emacs manual (or in Emacs: C-h r i string syntax <RET>).

In your case, the original command includes double-quotes:

gsettings set org.gnome.desktop.wm.keybindings switch-applications "['<Super>Tab']"

...which need to be backslashed in the string argument to shell-command:

(shell-command "gsettings set org.gnome.desktop.wm.keybindings switch-applications \"['<Super>Tab']\"")

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  • Thank you; this answer, as well as solving the problem, is something I didn't know that I didn't know.
    – Orixi
    Commented Feb 28, 2023 at 19:22
  • @Orixi Glad I could help. By the by, you can access the Emacs manual in Emacs itself with C-h r (C-h is a prefix argument that directs to many help functions.) Once the Emacs manual is open, you can hit i to search for a topic like string syntax. And welcome to the forum and Emacs!
    – kozina-adjacent
    Commented Mar 1, 2023 at 9:06
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    @Orixi Note that literally every delimited format (not only within Emacs) has this requirement if the delimiters themselves are to be allowed within the delimited text. The concept of encoding a would-be special character to prevent it being special is known as "escaping" (not uncommonly using backslashes, but it varies).
    – phils
    Commented Mar 1, 2023 at 10:48

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