You have an IP address in your network how will you find hostname and vice versa?

Question

Let's say I want to compare two csv files: file A and file B. They are both similarly built - the first column has product IDs (one product per row) and the columns provide some stats about the products such as sales in # and $.

I want to compare these files - see which product IDs appear in the first column of file A and not in B, and which in B and not A.
Finally, it would be very great if the result could be written into two new CSV files - one product ID per row in the first column. (no other data in the other columns needed)

This is the script I tried:

import csv

#open CSV's and read first column with product IDs into variables pointing to lists
A = [line.split(',')[0] for line in open('Afile.csv')]
B = [line.split(',')[0] for line in open('Bfile.csv')]

#create variables pointing to lists with unique product IDs in A and B respectively 
inAnotB = list(set(A)-set(B))
inBnotA = list(set(B)-set(A))

print inAnotB
print inBnotA

c = csv.writer(open("inAnotB.csv", "wb"))
c.writerow([inAnotB])

d = csv.writer(open("inBnotA.csv", "wb"))
d.writerow([inBnotA])

print "done!" 

But it doesn't produce the required results.
It prints IDs in this format:

247158132n

and nothing to the csv files.

Answer 1

IP to Hostname
To find a hostname in your local network by IP address

nmblookup -A <ip>

To find a hostname on the internet

host <ip>

Alternate method

install nbtscan (apt-get install nbtscan or yum install nbtscan)
nbtscan <ip>

Hostname To IP
Use host command i.e.

host queryhome.com
queryhome.com has address x.x.x.x