Update README

1 files changed, 6 insertions, 2 deletions

diff --git a/README.rst b/README.rst
index ba37d21..377ead8 100644
--- a/README.rst
+++ b/README.rst
@@ -13,7 +13,7 @@ Features
  - fixes broken CR/LF in headers
  - handles environment in a sane way (CGI scripts get HTTP-related env. vars from FastCGI parameters and inherit all the others from ``fcgiwrap``'s environment)
  - no configuration, so you can run several sites off the same ``fcgiwrap`` pool
- - passes CGI stderr output to ``fcgiwrap``'s stderr (this is by design but stderr could be also passed to FastCGI stderr stream)
+ - passes CGI stderr output to ``fcgiwrap``'s stderr or FastCGI stderr stream
 
 Installation
 ============
@@ -24,6 +24,8 @@ requirements
 
 ``fcgiwrap`` links to *dev-libs/fcgi* which can be obtained from http://www.fastcgi.com/ .
 
+``fcgiwrap`` also uses (but not requires) ``systemd`` for socket activation.
+
 procedure
 ---------
 To install::
@@ -40,4 +42,6 @@ usage
 -----
 Most probably you will want ``fcgiwrap`` be launched by `www-servers/spawn-fcgi <http://redmine.lighttpd.net/projects/spawn-fcgi>`_. Or you could use the author's Perl launcher - see the homepage for that.
 
-When running, ``fcgiwrap`` evaluates environment variables *DOCUMENT_ROOT* and *SCRIPT_NAME*, concatenates them and invokes the resulting executable (should it exist).
+There are two modes of ``fcgiwrap`` operation:
+ - when *SCRIPT_FILENAME* is set, its value is treated as the script name and executed directly.
+ - otherwise, *DOCUMENT_ROOT* and *SCRIPT_NAME* are concatenated and split back again into the script name and *PATH_INFO*. For example, given a *DOCUMENT_ROOT* of ``/www/cgi`` and *SCRIPT_NAME* of ``/subdir/example.cgi/foobar``, ``fcgiwrap`` will execute ``/www/cgi/subdir/example.cgi`` with *PATH_INFO* of ``/foobar`` (assuming ``example.cgi`` exists and is executable).