Updated description.

README.md

@@ -3,22 +3,50 @@
 Version 0.7.4, 23 March 2010
 
 ## Description
+
 This package is used to extract the revision and file information provided
-by the subversion revision control system.
+by the [Subversion](http://subversion.apache.org/) revision control system.
+
+To maintain different versions of a document or to keep track on the development of one,
+the document is kept under a revision control system like SCCS, CVS, or Subversion.
+This LaTeX package assumes you are using the Subversion system. To present the version
+information of a document, one needs to extract it from some kind of text inserted by
+the revision control system. Subversion offers therefore the `Id` keyword, which is
+expanded by the Subversion update command and contains a lot of useful information.
+This information is made available through this package. The information obtained
+from the expanded string are:
+
+* The filename,
+* the revision number,
+* the date and time of the last Subversion co command, and
+* name of the user who has done this action.
+
+For each of these items a macro is defined. When updating a file, the Subversion
+keywords should be contained in the updated source. Further, one has to set the
+Subversion property for keyword expansion of that file, e.g.
+
+```LaTeX
+svn propset svn:keywords "Id" svninfo.dtx
+```
 
 ## Installation
+
 To install: unpack and
-```
+
+```shell
     make
 ```
+
 or execute the commands manually:
-```
+
+```shell
     latex svninfo.ins     // creates the file of this package
     latex svninfo.dtx     // create the package documentation
 ```
 
 The following files are created by 'latex svninfo.ins'
-```
+
+```shell
  svninfo.cfg
  svninfo.sty
  svninfo.perl
@@ -26,16 +54,21 @@ The following files are created by 'latex svninfo.ins'
 ```
 
 then copy the files
-```
+
+```shell
     svninfo.sty
     svninfo.cfg
 ```
+
 to a place where LaTeX can find it, e.g.,
-```
+
+```shell
     $HOME/tex/inputs
 ```
+
 and set the environment variable
-```
+
+```shell
     TEXINPUTS=$HOME/tex/inputs//:$TEXINPUTS
 ```
 
@@ -48,12 +81,14 @@ opinion) any later version.
 
 You are allowed to distribute this file under the condition that it is
 distributed together with all the following files:
-```
+
+```shell
    svninfo.ins
    svninfo.dtx
    Makefile
    README
 ```
+
 If you receive only some of these files from someone, complain!
 
 SPDX-License-Identifier: LPPL-1.3c+