README.md: add command-line usage instructions

README.md

@@ -10,6 +10,26 @@ See the HTML page for an explanation of the output format
 and additional usage instructions.
 
 
+Command-line use
+----------------
+
+You can pass in a "mystery string" and have it decoded in various ways.
+
+```
+bash$ 8bit 
+'W\x8b\xab': ['cp037', 'cp273', 'cp500', 'cp1026', 'cp1140']
+'\x8b\xaf\xa8': ['cp437', 'cp850', 'cp857', 'cp858']
+'\xef\xbb\xbf': ['cp1252', 'cp1254', 'cp1258', 'iso8859_9', 'iso8859_15', 'latin_1', 'palmos']
+'\xdd\xfd\xb9': ['hp_roman8']
+'\x95\xdf\xc0': ['mac_croatian']
+'\x95\xc8\xc0': ['mac_iceland', 'mac_roman', 'mac_romanian', 'mac_turkish']
+'\ufeff': ['utf-8']
+```
+
+There is also a `--table` option which lets you generate the web page
+or a textual rendering of the same information.
+
+
 License
 -------