Example Bot

import praw
import json

# What position on r/all would you like to post the comment on?
notificationThreshold = 100

# What subreddit?
subreddit = 'pcmasterrace'

# The message you want to send.  Use Reddit formatting here.
allMessage = """Hey, this is on r/all.
[Read the rules you numpties.](/r/pcmasterrace/about/rules)"""

# http://praw.readthedocs.io/en/v4.0.0/getting_started/authentication.html?highlight=oauth
# You will definitely have to change this.  See the above link for instructions

auth = []
auth['client_id'] = 'SI8pN3DSbt0zor'
auth['client_secret'] = 'xaxkj7HNh8kwg8e5t4m6KvSrbTI'
auth['user_agent'] = 'testscript by /u/fakebot3'
auth['username'] = 'fakebot3'
auth['password'] = '1guiwevlfo00esyy'

reddit = praw.Reddit(client_id= auth['client_id'],
                     client_secret= auth['client_secret'],
                     password= auth['password'],
                     user_agent= auth['user_agent'],
                     username= auth['username'])

f = open('./seenFrontPagePosts.txt', 'r+')
try:
    frontOld = json.loads(f.readline())
except:
    frontOld = []

# Get the top N posts from Reddit.  N is notificationThreshold
redditFrontPage = reddit.get_subreddit('all') \
                        .get_hot(limit=notificationThreshold)

# Loop through each post
for post in redditFrontPage:
    # See if the subreddit that the post is in is the subreddit
    # we care about.
    if str(post.subreddit) is subreddit:
        print "We have a post on r/all!"
        if str(post.id) not in frontOld:
            print "We haven't seen it before!"
            message = post.reply(allMessage)
            message.distinguish(sticky=True)
            frontOld.append(str(post.id))

f.seek(0)
f.truncate()
f.seek(0)
f.write(json.dumps(frontOld))
f.close()