Getting started comparing files
Meld lets you compare two or three text files side-by-side. You can start a new file comparison by selecting the File ▸ New... menu item.
Once you've selected your files, Meld will show them side-by-side. Differences between the files will be highlighted to make individual changes easier to see. Editing the files will cause the comparison to update on-the-fly. For details on navigating between individual changes, and on how to use change-based editing, see Dealing with changes.
Meld's file comparisons
There are several different parts to a file comparison. The most important parts are the editors where your files appear. In addition to these editors, the areas around and between your files give you a visual overview and actions to help you handle changes between the files.
On the left and right-hand sides of the window, there are two small vertical bars showing various coloured blocks. These bars are designed to give you an overview of all of the differences between your two files. Each coloured block represents a section that is inserted, deleted, changed or in conflict between your files, depending on the block's colour used.
In between each pair of files is a segment that shows how the changed sections between your files correspond to each other. You can click on the arrows in a segment to replace sections in one file with sections from the other. You can also delete, copy or merge changes. For details on what you can do with individual change segments, see Changing changes.
Saving your changes
Once you've finished editing your files, you need to save each file you've changed.
You can tell whether your files have been saved since they last changed by the save icon that appears next to the file name above each file. Also, the notebook label will show an asterisk (*) after any file that hasn't been saved.
You can save the current file by selecting the File ▸ Save menu item, or using the Ctrl+S keyboard shortcut.
Saving only saves the currently focused file, which is the file containing the cursor. If you can't tell which file is focused, you can click on the file to focus it before saving.