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
@@ -29,33 +29,33 @@ GLOBAL SETTINGS
 about-filter::
         Specifies a command which will be invoked to format the content of
         about pages (both top-level and for each repository). The command will
         get the content of the about-file on its STDIN, and the STDOUT from the
         command will be included verbatim on the about page. Default value:
         none.
 
 agefile::
         Specifies a path, relative to each repository path, which can be used
         to specify the date and time of the youngest commit in the repository.
         The first line in the file is used as input to the "parse_date"
         function in libgit. Recommended timestamp-format is "yyyy-mm-dd
         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
         value: "5".
 
 cache-repo-ttl::
         Number which specifies the time-to-live, in minutes, for the cached
         version of the repository summary page. Default value: "5".
 
 cache-root-ttl::
         Number which specifies the time-to-live, in minutes, for the cached
         version of the repository index page. Default value: "5".
 
 cache-scanrc-ttl::
         Number which specifies the time-to-live, in minutes, for the result
@@ -142,33 +142,33 @@ favicon::
 
 footer::
         The content of the file specified with this option will be included
         verbatim at the bottom of all pages (i.e. it replaces the standard
         "generated by..." message. Default value: none.
 
 head-include::
         The content of the file specified with this option will be included
         verbatim in the html HEAD section on all pages. Default value: none.
 
 header::
         The content of the file specified with this option will be included
         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
         will not be supported by cgit-1.0 (use root-readme instead). Default
         value: none.
 
 index-info::
         The content of the file specified with this option will be included
         verbatim below the heading on the repository index page. This setting
         is deprecated, and will not be supported by cgit-1.0 (use root-desc
         instead). Default value: none.
 
 local-time::
         Flag which, if set to "1", makes cgit print commit and tag times in the
         servers timezone. Default value: "0".
@@ -224,33 +224,34 @@ module-link::
 nocache::
         If set to the value "1" caching will be disabled. This settings is
         deprecated, and will not be honored starting with cgit-1.0. Default
         value: "0".
 
 noplainemail::
         If set to "1" showing full author email adresses will be disabled.
         Default value: "0".
 
 noheader::
         Flag which, when set to "1", will make cgit omit the standard header
         on all pages. Default value: none. See also: "embedded".
 
 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.
 
 remove-suffix::
         If set to "1" and scan-path is enabled, if any repositories are found
         with a suffix of ".git", this suffix will be removed for the url and
         name. Default value: "0". See also: scan-path.
 
 renamelimit::
         Maximum number of files to consider when detecting renames. The value
          "-1" uses the compiletime value in git (for further info, look at
           `man git-diff`). Default value: "-1".
 
 repo.group::
@@ -276,33 +277,34 @@ root-title::
 
 scan-hidden-path::
         If set to "1" and scan-path is enabled, scan-path will recurse into
         directories whose name starts with a period ('.'). Otherwise,
         scan-path will stay away from such directories (considered as
         "hidden"). Note that this does not apply to the ".git" directory in
         non-bare repos. This must be defined prior to scan-path.
         Default value: 0. See also: scan-path.
 
 scan-path::
         A path which will be scanned for repositories. If caching is enabled,
         the result will be cached as a cgitrc include-file in the cache
         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:
         none.
 
 section-from-path::
         A number which, if specified before scan-path, specifies how many
         path elements from each repo path to use as a default section name.
         If negative, cgit will discard the specified number of path elements
         above the repo directory. Default value: 0.
 
 side-by-side-diffs::
         If set to "1" shows side-by-side diffs instead of unidiffs per
         default. Default value: "0".
 
@@ -437,32 +439,52 @@ repo.url::
         setting specified for each repo. Default value: none.
 
 
 REPOSITORY-SPECIFIC CGITRC FILE
 -------------------------------
 When the option "scan-path" is used to auto-discover git repositories, cgit
 will try to parse the file "cgitrc" within any found repository. Such a
 repo-specific config file may contain any of the repo-specific options
 described above, except "repo.url" and "repo.path". Additionally, the "filter"
 options are only acknowledged in repo-specific config files when
 "enable-filter-overrides" is set to "1".
 
 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
 -------------------
 
 ....
 # Enable caching of up to 1000 output entriess
 cache-size=1000
 
 
 # Specify some default clone prefixes
 clone-prefix=git://example.com ssh://example.com/pub/git http://example.com/git
 
 # Specify the css url
 css=/css/cgit.css
 
 
 # Show extra links for each repository on the index page