1 files changed, 26 insertions, 4 deletions

diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index 65b210f..10b86f3 100644
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -44,3 +44,3 @@ cache-root::
         Path used to store the cgit cache entries. Default value:
-        "/var/cache/cgit".
+        "/var/cache/cgit". See also: "MACRO EXPANSION".
 
@@ -157,3 +157,3 @@ include::
         Name of a configfile to include before the rest of the current config-
-        file is parsed. Default value: none.
+        file is parsed. Default value: none. See also: "MACRO EXPANSION".
 
@@ -239,3 +239,4 @@ project-list::
         should loaded as git repositories. This must be defined prior to
-        scan-path. Default value: none. See also: scan-path.
+        scan-path. Default value: none. See also: scan-path, "MACRO
+        EXPANSION".
 
@@ -291,3 +292,4 @@ scan-path::
         before the scan-path directive will be applied to each repository.
-        Default value: none. See also: cache-scanrc-ttl, project-list.
+        Default value: none. See also: cache-scanrc-ttl, project-list,
+        "MACRO EXPANSION".
 
@@ -452,2 +454,22 @@ config files, e.g. "repo.desc" becomes "desc".
 
+MACRO EXPANSION
+---------------
+The following cgitrc options supports a simple macro expansion feature,
+where tokens prefixed with "$" are replaced with the value of a similary
+named environment variable:
+
+- cache-root
+- include
+- project-list
+- scan-path
+
+Macro expansion will also happen on the content of $CGIT_CONFIG, if
+defined.
+
+One usage of this feature is virtual hosting, which in its simplest form
+can be accomplished by adding the following line to /etc/cgitrc:
+
+        include=/etc/cgitrc.d/$HTTP_HOST
+
+
 EXAMPLE CGITRC FILE