How to get 'od' run?

Wed Nov 11 22:04:36 EST 2015

Hi,
I am learning python. I see a previous post has such code:
 >>> data = '"binääridataa"\n'.encode('utf-8') 
 >>> f = open('roska.txt', 'wb') 
 >>> f.write(data) 
 17 
 >>> f.close() 
The .encode methods produced a bytestring, which Python likes to display 
as ASCII characters where it can and in hexadecimal where it cannot: 
 >>> data 
 b'"bin\xc3\xa4\xc3\xa4ridataa"\n' 
An "octal dump" in characters (where ASCII, otherwise apparently octal) 
and the corresponding hexadecimal shows that it is, indeed, these bytes 
that ended up in the file: 
$ od -t cx1 roska.txt 
When I run the above line with python 2.7, it does not recognize 'od'.
Is it from a package? Or some internal function?
Thanks,