Often you may need to compare two text files to see the differences. Notepad++ is a very useful free text editor and you can easily add a free plug-in called 'Compare' to add this functionality:
Install Notepad++ if it's not already installed.
Check in Notepad++ that the Compare plugin is installed
With Notepad++ on the screen:
Click Plugins | Show Plugin Manager
Click Compare in the list and click Install
Accept the prompts...
Notepad++ will restart
Now on the Plugins menu you'll see the Compare option.
Normally the above is fine but in the past and possibly if you are troubleshooting, the following manual installation method might be useful:
Download the Compare plug-in for Notepad++
The download file is a zip, open it and extract the DLL inside. Copy this DLL file to:
Start Notepad++ and now on the Plugins menu you can find the Compare option.
Using Compare in Notepad++
Let's say for example we have two text files - here's what to do:
Open both files in Notepad++
Click Plugins | Compare | Compare (or press Alt-D)
You'll see something similar to the following:
In our example it shows that in file1.txt on the left one line is present that is not there in file2.txt. Also in file2.txt on the right an additional line was added. Of course this is a very simple test but if you have a larger file you can use the Nav Bar to jump to where there are differences.
In the above I was comparing large files. After running the Compare I saw in the Nav Bar that there were two lines (see the orange arrow in the image above) indicating two differences. I clicked and it took me to where the difference was. You can see some text is missing from one line in file2.txt.
It's very fast, even with very large files. It's also easy to use especially if you are already using Notepad++ for other work. Of course this can be used to compare all kinds of data such as log files, programming code or maybe CSV data files, etc. Compare for Notepad++ is excellent!
Recommended: 8 /10
If you want to compare two Excel worksheets please see my previous article on this subject which explains about using an add-on for Excel to compare files inside Excel:
Updated: August 2015
Notepad++ has a plugin installer built into it now. I updated this document to reflect this but I also left the manual download and installation steps just in case they are needed by anyone.