[TYPO3-english] RealURL - can I strip a subdir (= installation folder) from the URL?

[Erich Schreiber]

Hi,

I'm working with a TYPO3 installation (Linux host, Apache) which is
located in a subdirectory t3/ that shows up in the URL like
sample.com/t3/my-page/. RealURL and mod_rewirte are configured and are
working correctly.

Is it possible to strip this folder t3/ from the virtual URL? If yes,
how can this be done? If no, can this be accomplished with CoolURI?

I've done quite some online research and see that this is a recurring
question and people fiddle with RewriteBase (mod_rewrite) and
absRefPrefix (RealURL), etc. But I found no convincing reports of
success.

Remapping the webroot to t3/ via httpd.conf is no option for us, as we
run several parallel TYPO3 installations in this account. t3/ is the
production version, the others are training versions, older versions
for reference, etc. Only the one in t3/ needs to be mapped to the
webroot.

Erich