cgitrc.5.txt: describe macro expansion of cgitrc options

This is a new feature in cgit-0.9 which was formerly undocumented.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

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
@@ -41,9 +41,9 @@ agefile::
         hh:mm:ss". Default value: "info/web/last-modified".
 
 cache-root::
         Path used to store the cgit cache entries. Default value:
-        "/var/cache/cgit".
+        "/var/cache/cgit". See also: "MACRO EXPANSION".
 
 cache-dynamic-ttl::
         Number which specifies the time-to-live, in minutes, for the cached
         version of repository pages accessed without a fixed SHA1. Default
@@ -154,9 +154,9 @@ header::
         verbatim at the top of all pages. Default value: none.
 
 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".
 
 index-header::
         The content of the file specified with this option will be included
         verbatim above the repository index. This setting is deprecated, and
@@ -236,9 +236,10 @@ noheader::
 
 project-list::
         A list of subdirectories inside of scan-path, relative to it, that
         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".
 
 readme::
         Text which will be used as default value for "repo.readme". Default
         value: none.
@@ -288,9 +289,10 @@ scan-path::
         directory. If project-list has been defined prior to scan-path,
         scan-path loads only the directories listed in the file pointed to by
         project-list. Be advised that only the global settings taken
         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".
 
 section::
         The name of the current repository section - all repositories defined
         after this option will inherit the current section name. Default value:
@@ -449,8 +451,28 @@ options are only acknowledged in repo-specific config files when
 Note: the "repo." prefix is dropped from the option names in repo-specific
 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
 -------------------
 
 ....