What Git command allows you to add only *specific linesfrom a modified file to the staging area, leaving other changes in the working directory?

The Git command that allows you to add only specific lines from a modified file to the staging area, leaving other changes in the working directory, is `git add -p` or its long form, `git add --patch`.

When you execute `git add -p`, Git enters an interactive mode. It scans all modified files in your working directory. The working directory refers to the actual files on your file system that you are currently editing. Git then identifies all changes in these files by comparing them against the version currently in the staging area (or the last commit if the file is not yet staged). It breaks down these changes into discrete, contiguous blocks called 'hunks'. A hunk is a logical group of added, deleted, or modified lines.

For each hunk it finds, Git presents the changes to you and prompts you to decide whether to stage that particular hunk. The staging area, also known as the index, is an intermediate area where Git collects changes you intend to include in your next commit. You are given several options for each hunk:

- y (yes): Stages the current hunk, meaning those specific lines are moved from your working directory into the staging area.
- n (no): Does not stage the current hunk, leaving those specific lines as unstaged changes in your working directory.
- q (quit): Exits the interactive process without staging any more hunks.
- a (all): Stages the current hunk and all subsequent hunks in the current file.
- d (don't stage): Does not stage the current hunk and all subsequent hunks in the current file.
- s (split): Attempts to split the current hunk into smaller, more granular hunks if possible, allowing for finer-grained control over which specific lines to stage.
- e (edit): Opens the current hunk in your default text editor, allowing you to manually edit the patch. You can delete lines from the patch to prevent them from being staged, effectively selecting individual lines or parts of lines to stage.

By interactively selecting 'y' for specific hunks, or by using 's' to split and then 'y', or 'e' for precise line selection, you can meticulously control which lines or blocks of changes from a modified file are added to the staging area. Any changes you choose not to stage will remain in your working directory, visibly different from the version in the staging area, and will not be included in the next commit until they are explicitly staged.