Validation of contents in txt file

All,
What is the best way to validate the contents in text file.
I have an .xls file with contents in it. May be 1000 records.
Sample :
13209713 STRO 08 08/26/2013 AI\F45 09/12/2013 001 LAWE D50 08/29/2013 R
002 LAWE A07 08/30/2013 R
003 LAWE A07 08/30/2013 R
006 LAWE A07 08/30/2013 R
013 LAWE S45 08/30/2013 R
015 LAWE D50 08/30/2013 R
016 LAWE D50 08/30/2013 R
017 LAWE D50 08/30/2013 R
018 LAWE A09 09/06/2013 R
019 LAWE A07 09/06/2013 R
020 LAWE S20 09/11/2013 R
here the mail key is "13209713" and this one is 1 out of 1000 records in excel file. Then I have a similar data in .txt file
Sample :
13209713 STRO 08 08/26/2013 RU/F45 09/02/2013 001 LAWE D50 08/29/2013 R
002 LAWE A07 08/30/2013 R
003 LAWE A07 08/30/2013 R
006 LAWE A07 08/30/2013 R
013 LAWE S45 08/30/2013 R
015 LAWE D50 08/30/2013 R
016 LAWE D50 08/30/2013 R
017 LAWE D50 08/30/2013 R
018 LAWE A09 09/06/2013 R
019 LAWE A07 09/06/2013 R
020 LAWE S20 09/11/2013 R
Here also the key is : "13209713"

Now I need to validate that the content in .xls match with .txt else show the ones not matching. What is the best way to deal with this. Any suggestions is highly appretiaged.