How can I expand/collapse a diff sections in Vimdiff?

When using Vimdiff to compare files, you can collapse or expand specific sections of the file using the folding feature, which helps you focus on the current differences and avoid being distracted by other content in the file. The following are the specific steps to expand and collapse different sections in Vimdiff:

1. Expand Folding:

   • In Vimdiff, the folding feature is enabled by default. You can expand the current folded region using the zo command.
   • To expand all fold levels under the current cursor position, you can use the zO command.

2. Collapse Folding:

   • Use the zc command to fold the currently expanded region.
   • To fold all fold levels containing the current line, you can use the zC command.

3. Toggle Folding State:

   • Using the za command, you can toggle the fold state of the current line. If it is expanded, it will be folded; if it is folded, it will be expanded.
   • Similarly, the zA command toggles the state of all fold levels containing the current line.

4. Expand or Collapse All Folds:

   • Use the zR command to expand all folds in the document.
   • Use the zM command to fold all foldable regions in the document.

Practical Scenarios

Suppose you are comparing two versions of source code, where one file has many small changes distributed throughout the file. If you want to focus on the current differences, you can fold all unchanged sections and only view sections with larger differences. Using the above commands, you can quickly expand or collapse specific regions to review and edit the code more effectively.

These folding commands in Vimdiff provide a highly flexible approach to browsing and editing files, especially when handling large files or complex differences. By appropriately using the folding feature, you can improve productivity and reduce errors.