Set environment variable across all systemd services

Edit

all env environment service set systemd user variable variables

System services:

mkdir -p /etc/systemd/system.conf.d/

cat <<"EOF" > /etc/systemd/system.conf.d/override.conf
[Manager]
DefaultEnvironment=FOO=bar
EOF

systemctl daemon-reload

User services:

mkdir -p "$HOME/.config/systemd/user.conf.d/"

cat <<"EOF" > "$HOME/.config/systemd/user.conf.d/override.conf"
[Manager]
DefaultEnvironment=FOO=bar
EOF

systemctl --user daemon-reload