What is commit history in Git?

The commit history in Git is the chronological chain of all saved changes in a repository.

Simply put: it is a log in which Git records who, when, and exactly what changed in the project.

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#What a commit is in this context

Each commit is:

• a snapshot of the project's state at a specific point in time;
• a recorded set of file changes;
• a point you can return to.

Commits are linked to each other: each commit references the previous one, forming a chain (history).

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#What the commit history contains

For each commit, Git stores:

• a unique identifier (hash), for example a3f5c9e
• the author of the changes
• the date and time
• the commit message
• the file changes (diff)
• the parent commit (or several, if it is a merge)

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#What the history looks like in practice

The commit history is usually viewed with the command:

It shows the list of commits from newest to oldest:

• the latest commit is the current state of the branch
• below it are all the previous steps of development

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#Why the commit history is needed

The commit history lets you:

• understand how the project evolved
• find when and by whom a change was made
• roll back to a previous state
• compare file versions
• safely experiment with code

In interviews this is often phrased as:

Git stores not just files, but the entire history of their changes.

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#An important point for interviews

The commit history in Git is not just a list. It is a graph (usually a tree), because:

• there are branches
• there are merges
• a commit can have several parents

But in the simple case, it can be thought of as a chain of changes.