Cfxtrjtrk

I've run into a tricky situation.

I'm setting up a public-access computer, where it is desirable that people log in using the guest account.
The people who need to use the computer speak a lot of different languages.

The computer is an old one, and it's currently running Lubuntu 15.10, Lightdm login.

However, as it's only possible to switch system languages by logging out and back into an account, combined with the fact that the guest account gets wiped once it logs out...
A bit of a catch 22.

I'm probably going to have to solve this using some sort of a scripted language-picker.
I see two possible solutions, and those form my question(s):

Is there any way to change system language without a full logout?

Alternatively, is it possible to launch a script during a login? I'm thinking several different guest-account/skel alternatives, and making a symlink during login.

It's possible to change the environment variables LANG and LANGUAGE within the session, but it won't affect already running processes. So no, there is no practical way to do it without logging out.

Considering that lightdm-gtk-greeter already has a language selector for choosing the language when you log in to an ordinary account, the most elegant solution would probably be to somehow make use of that feature. Can't tell how, though...

The below example solution uses a wrapper script to let the user select the display language via a zenity dialog. The example includes English and Swedish; the languages you use must of course be installed. This solution should work with both unity-greeter and lightdm-gtk-greeter on later Ubuntu versions. I tested on 15.10 and 16.04.

Create /etc/guest-session/choose-language-wrapper.sh, give it this contents:

#!/bin/sh -e



# show zenity dialog only when launched from greeter

ONLYGUEST=true

for U in $(users); do

    if [ "${U%%-*}" != 'guest' ]; then

        ONLYGUEST=false

        break

    fi

done



if $ONLYGUEST && [ -x /usr/bin/zenity ]; then

    guestlang=$( zenity --list --title 'Select language' 

      --text 'Select language for the guest session' --radiolist 

      --column 'Pick' --column '' TRUE 'English' FALSE 'Swedish' )

    if [ "$guestlang" = 'English' ]; then

        echo 'export LANGUAGE=en_US' >> "$HOME/.profile"

        echo 'export LANG=en_US.UTF-8' >> "$HOME/.profile"

    elif [ "$guestlang" = 'Swedish' ]; then

        echo 'export LANGUAGE=sv' >> "$HOME/.profile"

        echo 'export LANG=sv_SE.UTF-8' >> "$HOME/.profile"

    fi

fi



exec /usr/lib/lightdm/lightdm-guest-session "$@"

and make it executable:

sudo chmod +x /etc/guest-session/choose-language-wrapper.sh

Then make lightdm use the wrapper script by creating this file:

$ cat /etc/lightdm/lightdm.conf.d/50-choose-guest-language.conf

[Seat:*]

guest-wrapper=/etc/guest-session/choose-language-wrapper.sh

After next reboot the zenity dialog should show up when launching a guest session from the greeter.