Foundations18 min

Why version control exists

Understand the idea

A folder of FINAL_v2_actualFINAL copies is not a history. It is a pile of guesses.

The idea

A folder of renamed copies does not tell you which file came from which. A names one whole snapshot and points at the snapshot it grew from. That chain is the history a team can share.

What changes

Nothing in the working files has to change for the idea to matter. What changes is that the group stops guessing. The holds the chain. People still edit files, but the saved history is no longer a second copy of the folder sitting beside the first.

Copies versus history
Habit	What you can answer	What you cannot
FINAL_v2 folders	Which file looks newest	Which edit came from which
A commit chain	What the folder was, and what it grew from	Nothing about parentage
A chat log of changes	Who claimed to edit something	The exact bytes at that moment

The command

You do not need a command to see the problem. Open the terminal on the next lesson and create a repository. Until then, read git log --oneline --graph as the sentence this track is building: each line is a named snapshot, and the graph is how they connect.

The mistake

Check your graph

When you do create the repository, the graph should show one initial commit and a main label. That single node is already more history than a pile of renamed folders.

Your repository

Version control exists so a team can name a snapshot, see who changed it, and return to it without keeping extra copies of the whole file.

Step 1
Look before a repository exists
A folder with no repository has nothing to return to. Run status. If you have not created a repository yet, Git says this is not a repository.
Step 2
The next lesson creates the history
Creating the repository is the first real snapshot. Continue to Repositories and the three states and use the create form there.

The editor edits the working tree. Start a repository and the files appear here.

Terminal

Follow the steps. Each command step can be placed in the terminal. Edit files in the editor, then stage them.

Supported command reference

init
add <path> | add .
commit -m "message" | commit --amend -m "message"
status
diff | diff --staged
log | log --oneline | log --graph | log --oneline --graph
show [ref]
branch | branch <name> | branch -d <name>
checkout <ref> | checkout -b <name> | switch <name> | switch -c <name>
merge <branch>
rebase <branch> | rebase -i <branch> | rebase --edit-todo <pick|drop|reword> <hash> [message] | rebase --continue | rebase --abort
cherry-pick <ref>
reset --soft <ref> | reset --mixed <ref> | reset --hard <ref>
revert <ref>
stash | stash list | stash pop | stash apply
restore <path> | restore --staged <path>
remote | remote add <name> <repo-slug>
clone <repo-slug> | git clone <repo-slug> | git fork <repo-slug>
fetch [remote] | pull [remote] [branch] | push [remote] [branch] | push --force [remote] [branch]
blame <path>
reflog
tag | tag <name> [ref] | tag -d <name>
bisect start | bisect good [ref] | bisect bad [ref] | bisect reset
config <key> <value> | config --list
write <path> <text> (workbench: edit the working tree)
issue new "title" | pr new <source> <target> "title" | review "comment" | review --request-changes "comment"

Commit graph

No commits yet. git init creates the first one.

Quiz

A quick check for understanding. Retry as often as you like; your learning path stays open.

01What problem do named snapshots solve?

They make files smallerThey let you return to a known folder stateThey replace the need to testThey hide who edited a file

02Why is FINAL_v2 a weak history?

The name does not say which copy is the source of truthGit cannot open files with numbersOnly one person can read itIt stores too many parents

Ready to call this one understood?

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