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Git Exercise
COP-3402

Table of Contents

1. Overview

In this project you will create a git repository and submit it to the grading server.

2. Log in to eustis

Be sure to do the first homework, which provides per-OS instructions for setting up ssh.

ssh into eustis, replacing NID with your UCF NID. 

ssh NID@eustis.eecs.ucf.edu

3. Configure git

You only need do this once for the entire semester.

3.1. Set user name

Replace "John Doe" with your full name. 

git config --global user.name "John Doe"

There will be no output. If you get any output, double-check the command and re-enter it.

Validation

git config --global user.name

The output should be the full name you put.

3.2. Set your email address

Replace "johndoe@example.com" with your ucf email address. 

git config --global user.email johndoe@example.com

Validation

git config --global user.email

The output should be the email address you put.

3.3. Set your editor to emacs

git config --global core.editor emacs

Validation

git config --global core.editor

The output should be emacs.

3.4. Explicitly set the default branch name to master

This is the current default and what our grading tools will expect when pulling your projects. 

git config --global init.defaultBranch master

Validation

git config --global init.defaultBranch

The output should be master.

4. Create your repository

You only need to do this once per project.

For instance, you only need to do this once for git, only once for hello, etc.

When following these directions for other projects, do not use git as the name of the repo, instead replace it with the name given in the project. For example, the hello project will have local directory ~/cop3402spring25/hello and URL gitolite3@eustis3.eecs.ucf.edu:cop3402/$USER/hello.

4.1. Create a new directory

mkdir -p ~/cop3402spring25/git

The output should be nothing. Note that -p will create all directories in the path if needed. If the path exists, it will not throw an error. The tilde ~ is an alias for your home directory, which on eustis is /home/net/NID for your NID.

Validation

ls -d ~/cop3402spring25/git

The output should be ~/cop3402spring25/git

If you see the following 

ls: cannot access '/home/net/NID/cop3402spring25/git': No such file or directory

then double-check your spelling and try creating the directory again.

4.2. Change the working directory to your new one

cd ~/cop3402spring25/git

The output will be nothing.

Validation

readlink -f ./

The output will be the full path to the current folder. Check it carefully. It should look like this: 

/home/net/NID/cop3402spring25/git

If you get an error like the following, 

-bash: cd: /home/net/NID/cop3402spring25/git: No such file or directory

then double-check your spelling and/or try creating the directory again.

4.3. Initialize the git repository

git init

The output should be 

Initialized empty Git repository in /home/net/NID/cop3402spring25/git/.git/

Double check the folder path to make sure it is correct. If not try creating the directory again.

Validation

git status

the output should be 

On branch master

No commits yet

nothing to commit (create/copy files and use "git add" to track)

The branch name should be master if not then go back to make sure git config is setup correctly.

Errors

If you see the following, 

hint: Using 'master' as the name for the initial branch. This default branch name
hint: is subject to change. To configure the initial branch name to use in all
hint: of your new repositories, which will suppress this warning, call:
hint: 
hint: 	git config --global init.defaultBranch <name>
hint: 
hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
hint: 'development'. The just-created branch can be renamed via this command:
hint: 
hint: 	git branch -m <name>

then go back to make sure git config is setup correctly.

  • Reinitialized accidentally

    The repository was already configured 

    Reinitialized existing Git repository in /home/net/NID/cop3402spring25/git/.git/

    you have already initialized your repo and can just continue.

4.4. Add your first file

echo "git project" > README.md

You should see no output.

Validation

readlink -f README.md

The output will be the full path of the file. Look at it carefully. It should look like 

/home/net/NID/cop3402spring25/git/README.md

Now enter 

git status

The output will now show that README.md is untracked, i.e., it has not been staged and commited to the local repository yet. It is only in your working tree. 

On branch master

No commits yet

Untracked files:
 (use "git add <file>..." to include in what will be committed)
 README.md

nothing added to commit but untracked files present (use "git add" to track)

Errors

If you see the following, 

fatal: not a git repository (or any parent up to mount point /home)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

then you haven't yet initialized your git repository or you are not in the right directory.

4.5. Stage the file

git add README.md

The output should be nothing

Validation

git status

This should result in the following output, which tells you that the file is staged but not commited yet: 

On branch master

No commits yet

Changes to be committed:
 (use "git rm --cached <file>..." to unstage)
 new file:   README.md

Double-check that the name of the file is README.md.

Errors

If you see 

fatal: not a git repository (or any parent up to mount point /home)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

then you haven't yet initialized your git repository or you are not in the right directory.

If you see 

fatal: pathspec 'README.md' did not match any files

then you haven't created the file yet.

4.6. Commit the file

Before committing, double-check that you configured your editor, 

git config --global core.editor

The output should be emacs (or the editor you selected). If not go back and be sure that git config is setup correctly.

To commit the file: 

git commit README.md

This will open up your editor automatically and present you with the following text 


# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# On branch master
#
# Initial commit
#
# Changes to be committed:
#       new file:   README.md
#

The cursor will already be on the first line. Type your commit message, e.g., "Add a README.md file", so that your text now looks like this: 

Add a README.md file
# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# On branch master
#
# Initial commit
#
# Changes to be committed:
#       new file:   README.md
#

Then save the file and exit the editor (in emacs this is Ctrl-x Ctrl-s then Ctrl-x Ctrl-c).

The output should be 

[master (root-commit) 0721d93] Add a README.md file
1 file changed, 1 insertion(+)
create mode 100644 README.md

0721d93 is the commit ID, which will differ for you.

See this description of good practices for writing commit message.

Validation

git status

The output should be 

On branch master
nothing to commit, working tree clean

Now enter 

git show

The output should be 

commit 0721d935b05f1e506621893a00afbd6a70b7d5c4 (HEAD -> master)
Author: John Doe <johndoe@example.com>
Date:   Thu Dec 19 11:20:43 2024 -0500

   Add a README.md file

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..74788a2
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+git project

The commit ID, author, and date should differ, but otherwise be the same. This is the changelog you have created.

Now enter 

git log

The output should be 

commit 0721d935b05f1e506621893a00afbd6a70b7d5c4 (HEAD -> master)
Author: John Doe <johndoe@example.com>
Date:   Thu Dec 19 11:20:43 2024 -0500

   Add a README.md file

The commit ID, author, and date should differ, but otherwise be the same. This is the history of changes, which shows only the commit ID, author, date, and first line of the commit message. Since this is your first change, there is only one log entry.

Errors

If you see 

fatal: not a git repository (or any parent up to mount point /home)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

then be sure you have initialized your git repository and are in the right directory.

If you see 

error: pathspec 'README.md' did not match any file(s) known to git

then make sure you have staged the file already.

If you see 

Aborting commit due to empty commit message.

then make sure you have typed in the commit message and saved the file.

4.7. Add the submission repository URL

Type the following: 

git remote add submission gitolite3@eustis3.eecs.ucf.edu:cop3402/$USER/git

The output should be nothing.

Validation

git remote -v

This should output the following 

submission	gitolite3@eustis3.eecs.ucf.edu:cop3402/NID/git (fetch)
submission	gitolite3@eustis3.eecs.ucf.edu:cop3402/NID/git (push)

except that NID should be your actual UCF NID, e.g., ab123456.

Errors

If you see 

error: remote submission already exists.

then you have already added the remote. Double-check that it is the right repo url and the remote name (submission). If not, do the following to remove the submission url and re-add it. 

git remote rm submission

then re-add the submission.

4.8. Set the upstream branch and push

git push --set-upstream submission master

You may see a request to check the host's fingerprint. You can say yes, although in general when connecting to a remote machine, you should independently confirm that the host's key matches the actual key on the server and that you trust the server.

Afterwards, the output should be something like this: 

Welcome to eustis.eecs.ucf.edu.

Please use your NID and NID password to log in.
Your NID should be 2 letters followed by 6 digits.

See http://t.cs.ucf.edu/help/eustis  for additional instructions.

Initialized empty Git repository in /home/gitolite3/repositories/cop3402/NID/git.git/
Enumerating objects: 3, done.
Counting objects: 100% (3/3), done.
Writing objects: 100% (3/3), 238 bytes | 238.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
To eustis3.eecs.ucf.edu:cop3402/NID/git
* [new branch]      master -> master
Branch 'master' set up to track remote branch 'master' from 'submission'.

This will push your local repository to the remote, grading repository URL. Additionally it will remember that your local repository's master branch is mapped to the submission repository's master branch, so you only need to the type git push for future submissions.

Validation

git status -sb

This should output the following 

## master...submission/master

which confirms the mapping between your local repo and the submission repo.

Now enter 

git branch -vv

The output should look like 

* master 0721d93 [submission/master] Add a README.md file

The commit ID will differ, but this also shows the submission/master is the remote repo mapped from your local repo.

Errors

If you see a login prompt like this 

Welcome to eustis.eecs.ucf.edu.

Please use your NID and NID password to log in.
Your NID should be 2 letters followed by 6 digits.

See http://t.cs.ucf.edu/help/eustis  for additional instructions.

NID@eustis.eecs.ucf.edu's password:

then make sure you have added the submission remote repo correctly. Check that the server URL starts with gitolite3@ and not your own NID. Your own NID will be later in the URL after the cop3402/, but it won't be the username before the @ symbol.

If you still see the above error, you have double- and triple- checked the URL, copied instead of hand-typed it, editing only the NID part and confirming that it is your NID, especially if you joined the class after the semester started, then it may be that you have not been given access to git yet. Please contact the instructor.

If you see 

fatal: 'submission' does not appear to be a git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

then make sure you have added the submission remote repo with the correct name submission. 

error: src refspec maste does not match any
error: failed to push some refs to 'master'

then make sure you have initialized your git repository.

If you see 

fatal: No configured push destination.
Either specify the URL from the command-line or configure a remote repository using

   git remote add <name> <url>

and then push using the remote name

   git push <name>

then be sure you have already set the upstream.

If you see 

To eustis3.eecs.ucf.edu:cop3402/NID/git
! [rejected]        master -> master (fetch first)
error: failed to push some refs to 'eustis3.eecs.ucf.edu:cop3402/NID/git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

then have already pushed a local repository to the grading repo and are trying to submitting a new git repo. Please see these instructions to clone your existing repo and add whatever new changes you have.

If you see a request to enter your password, double-check your NID and that you have logged into eustis and not eustis3.

5. Making change logs

5.1. Edit your README.md file

emacs README.md

Make changes to the file, e.g., 

git project

This project will exercise the use of the git version control tool on the command-line.

Then save and exit (for emacs, Ctrl-x Ctrl-s then Ctrl-x Ctrl-c).

Validation

Type 

git status

You should see the following, 

On branch master
Your branch is up to date with 'submission/master'.

Changes not staged for commit:
 (use "git add <file>..." to update what will be committed)
 (use "git restore <file>..." to discard changes in working directory)
 modified:   README.md

no changes added to commit (use "git add" and/or "git commit -a")

Double-check that you see "modified" for the file under "Changes not staged for commit". This means that your working tree has changed, but the changes aren't staged yet (or committed or pushed). In this state, your project has not been submitted and graders will not see what you see in your working tree.

Enter 

git diff

The output should look something like the following (with different commit IDs): 

diff --git a/README.md b/README.md
index 74788a2..2f11c4f 100644
--- a/README.md
+++ b/README.md
@@ -1 +1 @@
git project
+
+This project will exercise the use of the git version control tool on the command-line.

This will show you the differences you have made in your working directory.

Errors

If you see 

fatal: not a git repository (or any parent up to mount point /home)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

then you haven't yet initialized your git repository or you are not in the right directory.

If you see 

fatal: pathspec 'README.md' did not match any files

then you haven't created the file yet.

If you see 

nothing to commit, working tree clean

then you haven't modified README.md.

5.2. Stage the file

git add README.md

The output should be nothing

Validation

git status

This should result in the following output, which tells you that the change is staged but not commited yet: 

Your branch is up to date with 'submission/master'.

Changes to be committed:
 (use "git restore --staged <file>..." to unstage)
 modified:   README.md

Double-check that you see "modified:" with the filename under "Changes to be committed". p

Errors

If you see 

fatal: not a git repository (or any parent up to mount point /home)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

then you haven't yet initialized your git repository or you are not in the right directory.

If you see 

fatal: pathspec 'README.md' did not match any files

then you haven't created the file yet.

5.3. Commit the file

Before committing, double-check that you configured your editor, 

git config --global core.editor

The output should be emacs (or the editor you selected). If not go back and be sure that git config is setup correctly.

To commit the file: 

git commit README.md

This will open up your editor automatically and present you with the following text 


# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# On branch master
#
# Initial commit
#
# Changes to be committed:
#       new file:   README.md
#

The cursor will already be on the first line. Type your commit message, e.g., "Add a README.md file", so that your text now looks like this: 

Add a project description to README.md
# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# On branch master
#
# Initial commit
#
# Changes to be committed:
#       new file:   README.md
#

Then save the file and exit the editor (in emacs this is Ctrl-x Ctrl-s then Ctrl-x Ctrl-c).

The output should be something similar to 

[master 886c6f7] Add a project description to README.md
1 file changed, 1 insertion(+), 1 deletion(-)

The commit ID will differ for you.

Validation

git status

The output should be 

On branch master
Your branch is ahead of 'submission/master' by 1 commit.
 (use "git push" to publish your local commits)

nothing to commit, working tree clean

Notice that it says your branch is ahead of 'submission/master' by 1 commit. That means you have local change that are committed (i.e., no longer only in the working tree), but that are not yet synchronized with the remote grading repo.

Now enter 

git log

The output should be 

commit 886c6f73f32a6f283b9b0ff1a4a66d270926e1f0 (HEAD -> master)
Author: John Doe <johndoe@example.com>
Date:   Thu Dec 19 12:01:26 2024 -0500

   Add a project description to README.md

commit 0721d935b05f1e506621893a00afbd6a70b7d5c4 (submission/master)
Author: John Doe <johndoe@example.com>
Date:   Thu Dec 19 11:20:43 2024 -0500

   Add a README.md file

The commit ID, author, and date should differ, but otherwise be the same. Notice there are two log entries, one from the initial creation of README.md and one from your new edit. Also notice that after the commit idea there is (submission/master) for the first commit (on the bottom), which tells you that this is the latest commit synchronized with the remote grading repository. The latest commit (on top) says (HEAD -> master) which tells you that this is the most recent change of your local repository. The next step will be to push, which will ensure that any local (committed) changes are synchronized to the remote grading repository.

Errors

If you see 

fatal: not a git repository (or any parent up to mount point /home)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

then be sure you have initialized your git repository and are in the right directory.

If you see 

error: pathspec 'README.md' did not match any file(s) known to git

then make sure you have staged the file already.

If you see 

Aborting commit due to empty commit message.

then make sure you have typed in the commit message and saved the file.

5.4. Push the new changes

git push

The output should be something like this (but with different commit IDs). 

Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Writing objects: 100% (3/3), 264 bytes | 264.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
To eustis3.eecs.ucf.edu:cop3402/NID/git
  0721d93..886c6f7  master -> master

This will push any new changes to your local repository to the remote grading repository URL.

Validation

git log

commit 886c6f73f32a6f283b9b0ff1a4a66d270926e1f0 (HEAD -> master, submission/master)
Author: John Doe <johndoe@example.com>
Date:   Thu Dec 19 12:01:26 2024 -0500

   Add a project description to README.md

commit 0721d935b05f1e506621893a00afbd6a70b7d5c4
Author: John Doe <johndoe@example.com>
Date:   Thu Dec 19 11:20:43 2024 -0500

   Add a README.md file

Notice that now the latest commit (on top) has, after the commit ID, (HEAD -> master, submission/master), which means that both your local repo master and the remote grading repo submission/master are synchronized to the latest change.g

The commit ID will differ, but this also shows the submission/master is the remote repo mapped from your local repo.

Errors

If you see 

error: src refspec maste does not match any
error: failed to push some refs to 'master'

then make sure you have initialized your git repository.

If you see 

fatal: No configured push destination.
Either specify the URL from the command-line or configure a remote repository using

   git remote add <name> <url>

and then push using the remote name

   git push <name>

then be sure you have already set the upstream.

If you see 

To eustis3.eecs.ucf.edu:cop3402/NID/git
! [rejected]        master -> master (fetch first)
error: failed to push some refs to 'eustis3.eecs.ucf.edu:cop3402/NID/git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

then have already pushed a local repository to the grading repo and are trying to submitting a new git repo. Please see these instructions to clone your existing repo and add whatever new changes you have.

If you see a request to enter your password, double-check your NID and that you have logged into eustis and not eustis3.

6. Muscle Memory

Once you have configured git and setup a repo, the following is the workflow for making changes to your repository and synchronizing with the remote. 

emacs file.c
# edit, then exit and save (Ctrl-x Ctrl-s then Ctrl-x Ctrl-c)
git add file.c
git commit file.c
# enter a commit message, then exit and save (Ctrl-x Ctrl-s then Ctrl-x Ctrl-c)
git push
git status # to validate your work

7. (Optional) Deleting a file

7.1. Stage the deletion

Use 

git rm filename

to remove a file named "filename" from the repository. It will also remove it from the working directory.

You should see something like 

rm 'filename'

as the output. Then follow the same directions as editing or adding a file to commit and push the file deletion. Note that the deleted file will still be recorded in the repository's log.

Validation

Part of the output should contain something like the following: 

Changes to be committed:
 (use "git restore --staged <file>..." to unstage)
 deleted:    filename

There may be other information in the output, but this part shows that the file deletion is staged for commit. Once you commit the change the file will be removed from the local repo and, once pushed, from the remote repo.

Errors

If you see 

fatal: pathspec 'filename' did not match any files

then the file is not part of the git repository yet and you do not need to remove it.

8. (Optional) Cloning a fresh copy of your repo

8.1. Move your new local repo out of the way

mkdir -p ~/cop3402spring25/archive
mv ~/cop3402spring25/git ~/cop3402spring25/archive

Validation

There should be no output if this is successful.

Errors

If you see this 

mv: cannot overwrite '~/cop3402spring25/archive/git: Directory not empty

then you have already archived a git repository. Try instead creating a unique name, e.g., by adding additional numbers or letters to the target name, such as 

mv ~/cop3402spring25/git ~/cop3402spring25/archive/git2

Note that the target is now ~/cop3402spring25/archive/git2, with an additional git2 at the end, which moves and renames the ~/cop3402spring25/git directory.

A clever way to generate new names (that are less likely to conflict with an existing name) is to use the RANDOM environment variable, e.g., 

mv ~/cop3402spring25/git ~/cop3402spring25/archive/git.${RANDOM}

8.2. Clone your existing repo

Clone your repo: 

git clone gitolite3@eustis3.eecs.ucf.edu:cop3402/$USER/git ~/cop3402spring25/git

Validation

You should see something like the following in the output: 

remote: Enumerating objects: 3, done.
remote: Counting objects: 100% (3/3), done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
Receiving objects: 100% (3/3), done.

The number of objects may differ depending on your repo's contents.

Errors

  • File exists

    If you see 

    fatal: destination path '~/cop3402spring25/git already exists and is not an empty directory.

    then you have either forgotten to move your other repo out of the way or have already cloned this repo before. You can just enter ~/cop3402spring25/git and pull instead, i.e., 

    cd ~/cop3402spring25/git
git pull
  • Cloned an empty repo

    If you see something like 

    Initialized empty Git repository in /home/gitolite3/repositories/cop3402/NID/git.git/
warning: You appear to have cloned an empty repository.

    then it means you haven't yet pushed your repository yet. Go through the workflow to create your repository. If you still cannot clone it, double-check that you have typed the correct name of the repo.

  • Access denied to repo

    If you see 

    FATAL: R any cop3402/ab123546/git ab123456 DENIED by fallthru
(or you mis-spelled the reponame)
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

    then you may have mistyped your NID. For instance, above it is ab123546, which is supposed to ab123456, i.e., the 4 and 5 are swapped.

  • Access denied to eustis3

    If you see 

    Permission denied, please try again.

    double-check that you are on eustis.eecs.ucf.edu and not eustis3.eecs.ucf.edu. If your prompt looks like this 

    NID@eustis3:~$

    i.e., it has eustis3 or if you type the following 

    hostname

    and you see eustis3, then you are on the wrong server. Log out 

    exit

    then log back into eustis (not eustis3).

8.3. Copy over any material from you old repo

For example, if you want to copy over your latest, uncommitted README.md changes from the origina local repo, 

cp ~/cop3402spring25/archive/git/README.md ~/cop3402spring25/git

or use ~/cop3402spring25/git2 or whatever name you used when moving your repo.

There should be no output.

Validation

Enter 

git status

You should see (in part of your output) something like 

Changes to be committed:
 (use "git rm --cached <file>..." to unstage)
 new file:   README.md

which reflects the changes to the README.md that you have copied over. If you don't see this, the the README.md either is not different from the original repo or you have not committed it yet. In the the latter case, make sure you have completely setup your repo.

Errors

If either directory does not exist, then double-check the names and that they you have followed the previous directions.

9. Grading schema

Criterion Points
The git repo exists 3
The repo contains README.md .5
There are at least two log entries .5
TOTAL 4

10. Grading script

Log in to eustis and run the following to get the script 

mkdir -p ~/grading/cop3402spring25
cd ~/grading/cop3402spring25
wget https://www.cs.ucf.edu/~gazzillo/teaching/cop3402spring25/files/git_grader.sh

Then to grade, run the following, replacing NID with your UCF NID, 

bash git_grader.sh $USER

Note that this grade does not include any late penalty and therefore may differ from your actual grade in webcourses.

Author: Paul Gazzillo

Created: 2025-03-12 Wed 11:02

Validate