I do which just add a ralt_switch to English(Dvorak-US) keyboardsudo sed -i 249i\    include 'level3(ralt_switch)' \          /usr/share/X11/xkb/symbols/ussudo dpkg-reconfigure xkb-dataRestart and you get a non-functional keyboard at login where you cannot type anything. You have to fix the file then with Live USB back, as described here with chroot. After restart, the file /usr/share/X11/xkb/symbols/us with much more changes; each environment has now include 'level3(ralt_switch)' at the end of their sections66,67d65< <     include level3(ralt_switch)130,131d127< <     include level3(ralt_switch)185,186d180< <   include level3(ralt_switch)248d241<     include 'level3(ralt_switch)'313,314d305< <     include level3(ralt_switch)359,360d349< <     include level3(ralt_switch)600,601d588< <     include level3(ralt_switch)655,656d641< <     include level3(ralt_switch)720,721d704< <     include level3(ralt_switch)787,788d769< <     include level3(ralt_switch)831,832d811< <    include level3(ralt_switch)851d829<     include level3(switch)898,899d875< <     include level3(switch)929,930d904< <     include level3(switch)979,980d952< <     include level3(switch)1038,1039d1009< <    include level3(ralt_switch)1102,1103d1071< <    include level3(ralt_switch)1188,1189d1155< <   include level3(ralt_switch)1233,1234d1198< <         include level3(alt_switch)1277,1278d1240< <     include level3(ralt_switch)1318,1319d1279< <     include level3(ralt_switch)1365,1366d1324< <     include level3(ralt_switch)1415,1416d1372< <     include level3(ralt_switch)I generated those lines by sudo sed -i.bak ${pos[1]}i\    include 'level3(ralt_switch)' /usr/share/X11/xkb/symbols/usI am thinking how to double quotes in include level.... Maybe ...System: Ubuntu 16.04 64 bitLinux kernel: 4.6Linux kernel options: wlHardware: Macbook Air 2013-mid 
How can I add an include line to an XKB configuration file?
xkb
Correct answer by meuh: have double quotes and escape them like sudo sed -i.bak  \    ${pos[1]}i\ include \level3(ralt_switch)\ /usr/share/X11/xkb/symbols/us