In Fedora Workstation (using Gnome 3) keyboard shortcut for changing input source defaults to using Super+Space key combination and Super+Shift+Space for switching it back. But what happens if you want to use your “modifiers” to change your keyboard layout?
Launching System Settings and changing keyboard shortcuts won’t allow you to use “modifier only” shortcuts, you’ll need to specify one more “regular” key for it to accept your new shortcut. Some guides are suggesting that you can change this option via Gnome Tweak tool but unfortunately I don’t see this option, do you? ;-)
Do not despair! As always, there’s a solution for this problem. You can use following commands to set your shortcuts directly with gsettings. To set Alt+Left Shift as your “Switch input source” use following command:
gsettings set org.gnome.desktop.wm.keybindings switch-input-source "['<Alt>Shift_L']"
and to set Alt+Control+Left shift as your “Switch to previous input source” use this command:
gsettings set org.gnome.desktop.wm.keybindings switch-input-source-backward "['<Alt><Control>Shift_L']"
If you don’t want to use gsettings command and you want more “graphical way” you can use dconf to do the same thing. Install dconf with:
sudo dnf install -y dconf
open it up and navigate to org > gnome > desktop > wm > keybindings to change the options switch-input-source and switch-input-source-backward.