What 's the difference between git reset -- mixed , -- soft , and -- hard ?

Git is a powerful version control system that enables developers to manage and track source code history using various commands. The git reset command is used to reset the current HEAD to a specific state. There are three primary modes: mixed, soft, and hard. These modes differ in scope and behavior, and understanding their distinctions is crucial for effective Git usage.

1. Git Reset Soft

When using git reset --soft, it moves the HEAD to another commit without altering the staging area or working directory. This is useful for undoing committed changes while preserving the changes in the staging area, allowing you to re-edit and re-commit them without disrupting your current work.

Example: Suppose you have the following commit history:

shell
A -- B -- C (HEAD)

If you run git reset --soft B, commit C is reverted, but the changes from C remain in the staging area, allowing you to re-edit and re-commit them.

2. Git Reset Mixed

git reset --mixed is the default mode for the git reset command. This mode moves the HEAD to the specified commit and resets the staging area, but does not modify the working directory. This allows developers to review and re-stage changes.

Example: Continuing with the previous example, if you run git reset --mixed B, the changes from C are removed from the HEAD and cleared from the staging area, but they remain in the working directory, allowing you to decide whether to re-edit and re-commit them.

3. Git Reset Hard

Using git reset --hard resets the HEAD, staging area, and working directory to the specified commit. This is a dangerous operation as it discards all current work progress. It is useful when you want to completely revert to a specific state and discard all subsequent changes.

Example: In the same scenario, executing git reset --hard B not only reverts commit C but also clears all changes from the staging area and working directory, returning you completely to the state of commit B.

Summary

The choice of reset mode depends on your objective:

• --soft preserves changes and moves them to the staging area.
• --mixed preserves changes but removes them from the staging area.
• --hard completely discards all changes, returning to a clean state.

When using git reset, ensure you understand the impact of these commands, especially with --hard, as it may result in the loss of uncommitted changes.