Do a diff in Notepad++?

Performing a diff (difference comparison) in Notepad++ is straightforward and highly useful for identifying changes between two text files. This functionality is typically achieved using the Compare plugin.

How to Perform a Diff in Notepad++

To compare two files in Notepad++ and view their differences, follow these simple steps:

Step-by-Step Guide

Launch Notepad++ and Open Files:
- Start Notepad++.
- Open your first file (e.g., original_file.txt) by navigating to File > Open or dragging it into the editor.
- Open your second file (e.g., modified_file.txt) in the same Notepad++ instance. Ensure both files are open and visible as tabs.
Initiate Comparison:
- With both files open, click on the Plugins menu in the Notepad++ toolbar.
- Hover over Compare (if installed).
- Select Compare from the submenu.
- Notepad++ will then analyze the two active files.
Review Comparison Results:
- Notepad++ will highlight the differences between the two files directly within the editor. Typically, it uses distinct colors to indicate added lines, deleted lines, and modified lines, making it easy to visually identify changes.

Installing the Compare Plugin

The "Compare" feature in Notepad++ is not built-in by default but is provided by a popular plugin. If you don't see the Compare option under the Plugins menu, you'll need to install it first.

Here’s how to install the Compare plugin:

Access Plugin Admin:
- Go to Plugins > Plugins Admin... in Notepad++.
Search for Compare:
- In the "Plugins Admin" window, use the search bar or scroll down to find "Compare" in the "Available" tab.
Install Plugin:
- Check the box next to "Compare" and click the Install button.
- Notepad++ will prompt you to restart the application to complete the installation. Allow it to restart.

Once Notepad++ relaunches, the Compare plugin will be active, and you can follow the steps above to perform diffs.

Understanding Diff Highlights

The Compare plugin uses a color-coding system to visualize differences:

Green: Typically indicates lines that have been added to the second file but are not present in the first.
Red: Often signifies lines that have been deleted from the first file or are missing in the second.
Orange/Yellow: Usually highlights lines that have been modified, with specific character differences often shown in a darker shade or different color within the line.
Blue (or similar): May indicate lines that have moved position between the two files.

Navigating Differences

The Compare plugin also provides tools to help you navigate through the changes efficiently:

Next Difference: Go to Plugins > Compare > Next Diff or use the dedicated toolbar buttons (often arrows) to jump to the next identified difference.
Previous Difference: Similarly, Plugins > Compare > Previous Diff or the corresponding toolbar button will take you to the prior change.
Clear Active Comparison: When you're done reviewing, you can clear the highlights by going to Plugins > Compare > Clear Active Comparison or by simply closing the files.

Practical Applications of Diff

Comparing files is invaluable for various tasks, including:

Code Review: Identifying changes in source code between versions.
Document Version Control: Tracking modifications in text documents, configurations, or scripts.
Debugging: Pinpointing where a file might have been altered, leading to unexpected behavior.
Data Analysis: Comparing data sets to find discrepancies.

Comparison Summary

Feature	Description	How to Access
Plugin Installation	Required for diff functionality.	`Plugins > Plugins Admin...`
Open Files	Load the two files you wish to compare.	`File > Open`
Initiate Comparison	Start the diff process between the currently active files.	`Plugins > Compare > Compare`
View Differences	Visual highlighting of additions, deletions, and modifications.	Automatic after comparison
Navigate Diffs	Jump between different change locations.	`Plugins > Compare > Next/Previous Diff`
Clear Comparison	Remove the diff highlights once analysis is complete.	`Plugins > Compare > Clear Active Comparison`

For more information and to download Notepad++, visit the Notepad++ Official Website.