Duplicate of How to swap Command and Control keys with xkb step by step?
In 16.04, here's the way I finally got this to work.
Xmodmap doesn't work universally in all apps, gnome tweak tool lacked the function, dconf editing a custom altwin2 key swap (like the main answer here) failed, so I was tearing my hair out until I combined several answers into this complete, simple, and elegant solution:
gksudo gedit /usr/share/X11/xkb/symbols/pc
change it to:
default partial alphanumeric_keys modifier_keys
xkb_symbols "pc105" {
key <ESC> { [ Escape ] };
// The extra key on many European keyboards:
key <LSGT> { [ less, greater, bar, brokenbar ] };
// The following keys are common to all layouts.
key <BKSL> { [ backslash, bar ] };
key <SPCE> { [ space ] };
include "srvr_ctrl(fkey2vt)"
include "pc(editing)"
include "keypad(x11)"
key <BKSP> { [ BackSpace, BackSpace ] };
key <TAB> { [ Tab, ISO_Left_Tab ] };
key <RTRN> { [ Return ] };
key <CAPS> { [ Caps_Lock ] };
key <NMLK> { [ Num_Lock ] };
key <LFSH> { [ Shift_L ] };
key <LCTL> { [ Alt_L ] };
key <LWIN> { [ Super_L ] };
key <RTSH> { [ Shift_R ] };
key <RCTL> { [ Alt_R ] };
key <RWIN> { [ Super_R ] };
key <MENU> { [ Menu ] };
// Beginning of modifier mappings.
modifier_map Shift { Shift_L, Shift_R };
modifier_map Lock { Caps_Lock };
modifier_map Control{ Control_L, Control_R };
modifier_map Mod2 { Num_Lock };
modifier_map Mod4 { Super_L, Super_R };
// Fake keys for virtual<->real modifiers mapping:
key <LVL3> { [ ISO_Level3_Shift ] };
key <MDSW> { [ Mode_switch ] };
modifier_map Mod5 { <LVL3>, <MDSW> };
key <ALT> { [ NoSymbol, Control_L, Control_R ] };
//include "altwin(meta_alt)"
key <LALT> { [ Control_L ] };
key <RALT> { [ Control_R ] };
modifier_map Mod1 { Alt_L, Alt_R, Meta_L, Meta_R };
key <META> { [ NoSymbol, Meta_L, Meta_R ] };
modifier_map Mod1 { <META> };
key <SUPR> { [ NoSymbol, Super_L ] };
modifier_map Mod4 { <SUPR> };
key <HYPR> { [ NoSymbol, Hyper_L ] };
modifier_map Mod4 { <HYPR> };
// End of modifier mappings.
key <OUTP> { [ XF86Display ] };
key <KITG> { [ XF86KbdLightOnOff ] };
key <KIDN> { [ XF86KbdBrightnessDown ] };
key <KIUP> { [ XF86KbdBrightnessUp ] };
};
hidden partial alphanumeric_keys
xkb_symbols "editing" {
key <PRSC> {
type= "PC_ALT_LEVEL2",
symbols[Group1]= [ Print, Sys_Req ]
};
key <SCLK> { [ Scroll_Lock ] };
key <PAUS> {
type= "PC_CONTROL_LEVEL2",
symbols[Group1]= [ Pause, Break ]
};
key <INS> { [ Insert ] };
key <HOME> { [ Home ] };
key <PGUP> { [ Prior ] };
key <DELE> { [ Delete ] };
key <END> { [ End ] };
key <PGDN> { [ Next ] };
key <UP> { [ Up ] };
key <LEFT> { [ Left ] };
key <DOWN> { [ Down ] };
key <RGHT> { [ Right ] };
};
Save.
rm -rf /var/lib/xkb/*
(I don't know if this is required, but I did it.)
Reboot.
