I updated /etc/default/locale, LANG=C.UTF-8, then reboot. ted@debian:~$ locale LANG=en_US.UTF-8 LANGUAGE= LC_CTYPE="en_US.UTF-8" LC_NUMERIC="en_US.UTF-8" LC_TIME="en_US.UTF-8" LC_COLLATE="en_US.UTF-8" LC_MONETARY="en_US.UTF-8" LC_MESSAGES="en_US.UTF-8" LC_PAPER="en_US.UTF-8" LC_NAME="en_US.UTF-8" LC_ADDRESS="en_US.UTF-8" LC_TELEPHONE="en_US.UTF-8" LC_MEASUREMENT="en_US.UTF-8" LC_IDENTIFICATION="en_US.UTF-8" LC_ALL=
ted@debian:~$ localectl System Locale: LANG=C.UTF-8 VC Keymap: us X11 Layout: us so my question number 1 is, how come localectl and locale reports are different? and I traced the processes from parent to child, in /proc/ID/environ: systemd --user #LANG=C.UTF-8 gnome-terminal-server #LANG=en_US.UTF-8, GDM_LANG=en_US.UTF-8 bash #LANG=en_US.UTF-8, GDM_LANG=en_US.UTF-8 question number 2 is, which config file changed the LANG and added GDM_LANG? btw, I searched the files in the following locations, either there is no such file or there are no relevant settings in the file: /usr/lib/systemd/user/ ~/.local/share/systemd/user/ /etc/systemd/user/ ~/.config/systemd/user/ I also searched in dconf-editor, and changed org.gnome.system.location from custom value en_US.UTF-8 to default. Doesn't help. Any reference/links about how systemd/gnome environment variable works, and information about locales will be appreciated. Ted