The wpa_cli man page is very uncomplete. I browsed hours to find how I can manually select a network among the "known networks" listed in the /etc/wpa_supplicant/wpa_supplicant.conf file.
Therefore the only need would be to say "wpa_cli select_network <id>", but at least the *_network commands are not listed in the manual page. I did not find them on the web, only the README.gz in /usr/share/doc folder could help; the command is listed there after lines and lines of license related stuff etc.