diff -r fd53f083768c Doc/library/sys.rst
--- a/Doc/library/sys.rst	Sat Mar 08 21:40:29 2014 -0500
+++ b/Doc/library/sys.rst	Mon Mar 17 23:57:54 2014 +0100
@@ -27,6 +27,40 @@
 
    To loop over the standard input, or the list of files given on the
    command line, see the :mod:`fileinput` module.
+   
+   However, one important thing to note here is that the command line arguments are 
+   treated as bytestrings. Sometimes, the arguments must be passed as bytes while in 
+   some situations, e.g. when passing a path, there is no need of any particular 
+   characted encoding in Unix. 
+
+   Consider an example of a brief python program `a.py`::
+       import sys
+
+       print(sys.argv[1])
+       print(b'bytes')
+
+   When the above program is executed as python3.4 a.py éléphant, it prints the 
+   expected output as follows::
+       éléphant
+       b'bytes'
+
+   But if we pass the argument, for eg. 
+   python3.4 a.py `echo éléphant|iconv -t latin1` in a different encoding,
+   we obtain a UnicodeEnodeError. This is because those bytes that are passed are 
+   invalid UTF-8 arguments and hence can't be encoded as such for writing to the console.
+
+   The best solution is to use the application level knowledge of the correct encoding 
+   to reinterpret the command line argument inside the application, as in the following code::
+
+       $ python3.4 -c "import os, sys; print(os.fsencode(sys.argv[1]).decode('latin-1'))" 
+         `echo éléphant|iconv -t latin1`
+       éléphant
+
+   The os.fsencode function invocation reverses the transformation Python applied 
+   automatically when processing the command line arguments. The decode('latin-1') 
+   method invocation then performs the correct conversion in order to get a 
+   properly decoded string.
+
 
 
 .. data:: base_exec_prefix