Let's make a new text file called mars.txt:
$ nano mars.txt
In this file, add the line:
Cold and dry, but everything is my favorite color
Exit and save the file. You can make sure everything saved by opening the file with
$ less mars.txt
Git has noticed a new file:
$ git status
On branch master
Initial commit
Untracked files:
(use "git add <file>..." to include in what will be committed)
mars.txt
nothing added to commit but untracked files present (use "git add" to track)
mars.txt is "untracked", meaning that it is a file in the repository that Git is not yet keeping track of. We tell Git to start keeping track with
$ git add mars.txt
Running $ git status again now shows
On branch master
Initial commit
Changes to be committed:
(use "git rm --cached <file>..." to unstage)
new file: mars.txt
Git now knows to keep track of changes to mars.txt, but we haven't yet commited these changes. Let's run the following command:
$ git commit -m "Start notes on Mars"
When we run git commit, Git takes everything we have told it to track with git add and stores a copy permanently inside the special .git directory.
The -m flag (for “message”) is used to record a short, descriptive, and specific comment that will help us remember later on what we did and why.
Good commit messages start with a brief (<50 characters) statement about the changes made in the commit. More detail can be added by following this summary line with a blank line and additional notes.
Checking the status again, we see
$ git status
On branch master
nothing to commit, working directory clean
We can see the commit we just made by checking the log
$ git log
commit b2d9be95e4bdd162758fe90d7ce08693563b4212 (HEAD -> master)
Author: Samantha Dixon <sam.dixon@berkeley.edu>
Date: Mon Jul 9 11:25:18 2018 -0700
Start taking notes on Mars
This log will show all of the commits made in reverse-chronological order.
Let's make more changes to the file. Using your favorite text editor, add another line to mars.txt. Running git status again, we see that Git has noticed the modification.
On branch master
Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git checkout -- <file>..." to discard changes in working directory)
modified: mars.txt
no changes added to commit (use "git add" and/or "git commit -a")
We can check the difference between the version last commited and the current version with
$ git diff
diff --git a/mars.txt b/mars.txt
index df0654a..4826d23 100644
--- a/mars.txt
+++ b/mars.txt
@@ -1 +1,2 @@
Cold and dry, but everything is my favorite color
+More notes...
Let's commit this new change:
$ git add mars.txt
$ git commit -m "Add more information about Mars"
Note that we have to add the Mars file before we make the commit. This is so that you can break your changes up into logical pieces, rather than commiting all changes at once. Think of git add as placing changes in a staging area, while git commit permanently records this staging area.
We'll spend a few minutes staging and committing changes to our new repository. Try new things like:
- Adding new subdirectories
- Committing many files at once