README update

README.rst

@@ -2,9 +2,44 @@
 
 nvchecker is now **in development**.
 
+Dependency
+==========
+- Python 3
+- Tornado
+- All commands used in your configuration files
+
+Running
+=======
+To see available options::
+
+  ./nvchecker --help
+
+Run with one or more configuration files::
+
+  ./nvchecker config_file_1 config_file_2 ...
+
+You normally will like to specify some "version files"; see below.
+
+Version Files
+=============
+Version files record which version of the software you know or is available. They are simple key-value pairs of ``(name, version)`` seperated by ``:`` ::
+
+  fcitx: 4.2.7
+  google-chrome: 27.0.1453.93-200836
+  vim: 7.3.1024
+
+Say you've got a version file called ``old_ver.txt`` which records all your watched software and their versions. To update it using ``nvchecker``::
+
+  ./nvchecker --oldverfile=old_ver.txt --verfile=new_ver.txt config.ini
+
+Compare the two files for updates (assuming they are sorted alphabetically; files generated by ``nvchecker`` are already sorted)::
+
+  comm -13 old_ver.txt new_ver.txt
+  # or say that in English:
+  comm -13 old_ver.txt new_ver.txt | sed 's/:/ has updated to version/;s/$/./'
+
 Configuration Files
 ===================
-
 The configuration files are in ini format. *Section names* is the name of the software. Following fields are used to tell nvchecker how to determine the current version of that software.
 
 See ``sample_config.ini`` for an example.
@@ -37,18 +72,3 @@ Other
 -----
 More to come. Send me a patch or pull request if you can't wait and have written one yourself :-)
 
-Dependency
-==========
-- Python 3
-- Tornado
-- All commands used in your configuration files
-
-Running
-=======
-To see available options:
-
-  ./nvchecker --help
-
-Run with one or more configuration files:
-
-  ./nvchecker config_file_1 config_file_2 ...