systemctl --user daemon-reload报错

运行 systemctl --user daemon-reload 时，遇到如下报错。

Failed to connect to bus: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined (consider using --machine=<user>@.host --user to connect to bus of other user)

解决方案，依次运行以下命令。

export XDG_RUNTIME_DIR="/run/user/$(id -u)"
export DBUS_SESSION_BUS_ADDRESS="unix:path=${XDG_RUNTIME_DIR}/bus"