"Remove Duplicate Lines" tools are software programs or online services that can be used to identify and eliminate duplicate lines from a given text document or file. These tools are commonly used by professionals and students who work with large amounts of data or information, as it can be time-consuming and tedious to manually sift through and remove duplicate lines.

The process typically involves the following steps:

1. The user inputs the text document or file into the tool.
2. The tool scans the text and identifies any duplicate lines.
3. The tool removes the duplicate lines and outputs a new version of the text without duplicates.

Most "Remove Duplicate Lines" tools are simple and user-friendly, allowing even those with limited technical skills to use them effectively. Some tools may also have additional features, such as the ability to ignore certain lines or customize the matching criteria for identifying duplicates.

Overall, "Remove Duplicate Lines" tools can be very useful for streamlining the data cleaning process and ensuring the accuracy and integrity of text documents and files.