appendNote.py

import  sys
import  re
from    enauath   import client
from    string    import Template


#Accepts the GUID(string) of the note you want to append
def appendNote(guid):
  
  #Get the note to be updated using the note's guid http://dev.evernote.com/documentation/reference/NoteStore.html#Fn_NoteStore_getNote
  note = client.get_note_store().getNote(guid, True, True, False, False)
  
  #Regular expressions used to replicate ENML tags.  These same tags will be used to "rebuild" the note with the existing note metadata
  xmlTag          = re.search('<\?xml.*?>', note.content).group()
  docTag          = re.search('<\!DOCTYPE.*?>', note.content).group()
  noteOpenTag     = re.search('<\s*en-note.*?>', note.content).group()
  noteCloseTag    = re.search('<\s*/en-note.*?>', note.content).group()
  breakTag        = '<br />'
  
  #Rebuild the note using the new content
  content           =  note.content.replace(xmlTag, "").replace(noteOpenTag, "").replace(noteCloseTag, "").replace(docTag, "").strip()
  content           += breakTag + " ".join(sys.argv[1:])
  template          =  Template ('$xml $doc $openTag $body $closeTag')
  note.content      =  template.substitute(xml=xmlTag,doc=docTag,openTag=noteOpenTag,body=content,closeTag=noteCloseTag)  
  
  #Update the note
  client.get_note_store().updateNote(note)
  
  #Return updated note (object) to the function
  return note

noteGuid     = "99fcbee2-3d3b-49e5-9686-ef808d07da15" 
print appendNote(noteGuid)
  

config.json

//Get Sandbox Dev Token - https://sandbox.evernote.com/api/DeveloperToken.action
//Get Account Dev Token - https://www.evernote.com/api/DeveloperToken.action

{ 
  "evernoteUser":{
    "sandbox_dev_token": "Enter Your Sandbox Dev Token", 
    "account_dev_token": "Enter Your Evernote Developer Token" 
  }
}

enauth.py

from evernote.api.client import EvernoteClient
import json

#Get the values for the sandbox dev token and  evernote account dev token from the config file. 
with open('config.json', 'r') as config_data:
  data = json.load(config_data)

sandbox = data['evernoteUser']['sandbox_dev_token']
account = data['evernoteUser']['account_dev_token']

#client = EvernoteClient(token=sandbox, sandbox=True)
client = EvernoteClient(token=account, sandbox=False)