If there is no configuration file in “$XDG_CONFIG_HOME/update-mirrors”,
try looking through directories specified in XDG_CONFIG_DIRS. If
XDG_CONFIG_DIRS is not specified, use “/etc/xdg”.
Now config files are searched for in this order:
- “$XDG_CONFIG_HOME/update-mirrors/config.sh”, or
“$HOME/.config/update-mirrors/config.sh” if XDG_CONFIG_DIR is not
defined.
- For each DIR in XDG_CONFIG_DIRS “$DIR/update-mirrors/config.sh” is
tried, or “/etc/xdg/update-mirrors/config.sh” if XDG_CONFIG_DIRS is
not defined.