I was having a heck of a time trying to figure out why I couldn't get 3 websites in subdirectories to work properly with wordpress network multisite.
All I needed was:
But in the wordpress multisite network panel it was listing them without the subdirectory even though I went through the correct installation process and entered in subdirectories.
The solution was to log into phpmyadmin and look for the 3 database entries for wp_options and edit the url and home entries manually! eg: http://domainname.com becomes http://domainname.com/ca
Very frustrating and wasted a whole day on this. I guess most people set up their sites on a subdomain instead of subdirectory because I could not find any faq help on this.