Git, the popular version control system, provides powerful tools for managing your project's history. One common task is undoing commits, and Git offers two main methods to achieve this: soft reset and hard reset.

Soft Reset:

When you perform a soft reset, Git moves the HEAD pointer to a specified commit while retaining all changes made in subsequent commits. This means the changes are staged and ready to be committed again if needed. Let's illustrate this with an example:

Assume we have the following commit history:

A -- B -- C -- D -- E (HEAD)

Now, if we want to reset back to commit C using a soft reset, we'd execute the following command:

git reset --soft HEAD~2

After running this command, our commit history will look like this:

A -- B -- C (HEAD) -- D -- E

Here, changes made in commits D and E are preserved and staged, allowing us to recommit them if necessary.

Hard Reset:

Conversely, a hard reset discards all changes made in subsequent commits, effectively reverting your project back to a previous state. Here's how it works:

Assuming the same commit history:

A -- B -- C -- D -- E (HEAD)

To perform a hard reset back to commit C, we use the following command:

git reset --hard HEAD~2

After executing this command, our commit history will look like this:

A -- B -- C (HEAD)

In this scenario, changes made in commits D and E are completely removed from the project.

Conclusion:

In summary, soft reset retains changes staged for a new commit, while hard reset discards all changes made in subsequent commits. It's crucial to use these commands with caution, especially hard reset, as it permanently removes changes. Understanding when to apply each method can greatly enhance your Git workflow and help maintain a clean project history.