Welcome to WebmasterWorld Guest from 220.127.116.11
Forum Moderators: goodroi
You still have to create all the soft links, but after that you can quickly make one change that will impact all sites.
The Linux command is "ln" to create a link, so if you were in the wwwroot directory of SiteA, you might type:
ln robots.txt /path/to/robots.txt
...where /path/to/robots.txt is your central copy.