All variables in the env output, and where they come from.
/bin/login sets HOME, USER, LOGNAME and SHELL by reading it
from /etc/passwd.
In theory (from a mailing list thread):
The environment variable LOGNAME is a convention from the early days of AT&T UNIX. USER has been around for the same time in the BSD community.
login(1) initializes the user and group IDs and the working directory, and sets the HOME, PATH, TERM, SHELL and USER environment variables.
And also in practice -
setup_environment
in busybox source.
HOME=/home/m
USER=m
LOGNAME=m
SHELL=/bin/sh
/etc/profile sets PATH and PAGER.
export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
export PAGER=less
/etc/profile.d/20locale.sh sets CHARSET, LANG and LC_COLLATE.
export CHARSET=${CHARSET:-UTF-8}
export LANG=${LANG:-C.UTF-8}
export LC_COLLATE=${LC_COLLATE:-C}
Resolved:
CHARSET=UTF-8
LANG=C.UTF-8
LC_COLLATE=C
Set by startxfce4 when it is started by lightdm:
cat /etc/xdg/xfce4/xinitrc | grep 'export XDG' 2
export XDG_MENU_PREFIX
export XDG_CURRENT_DESKTOP
export XDG_CONFIG_HOME
export XDG_CACHE_HOME
Resolved:
XDG_MENU_PREFIX=xfce-
XDG_CURRENT_DESKTOP=XFCE
XDG_CONFIG_HOME=/home/m/.config
XDG_CACHE_HOME=/home/m/.cache
Set by xfce4-terminaldocs.xfce.org when starting the shell running in the terminal:
- TERM
- COLORTERM
- DISPLAY: The X11 display of the terminal
- WINDOWID: The X11 window identifier of the terminal
TERM=xterm-256color
COLORTERM=truecolor
DISPLAY=:0.0
WINDOWID=8389164
Set by ~/.zshrc:
export EDITOR=emacs
Remaining
env
DBUS_SESSION_BUS_ADDRESS=unix:path=/tmp/dbus-hoCtpCoy38,guid=9ec5c4207ec60ef6327026176856125d
DESKTOP_SESSION=xfce
GDMSESSION=xfce
PANEL_GDK_CORE_DEVICE_EVENTS=0
PWD=/home/m/.config
SESSION_MANAGER=local/mars:@/tmp/.ICE-unix/2458,unix/mars:/tmp/.ICE-unix/2458
SHLVL=5
VTE_VERSION=8002
XAUTHORITY=/home/m/.Xauthority
XDG_CONFIG_DIRS=/etc/xdg
XDG_DATA_DIRS=/usr/local/share:/usr/share
XDG_GREETER_DATA_DIR=/var/lib/lightdm-data/m
XDG_RUNTIME_DIR=/run/user/1000
XDG_SEAT=seat0
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
XDG_SESSION_CLASS=user
XDG_SESSION_DESKTOP=xfce
XDG_SESSION_ID=c2
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0
XDG_SESSION_TYPE=x11
XDG_VTNR=7