Git: Tutorial
Submission of all work during BI-3DT (except for physical prints) is done using Git. The Git server used is GitHub. This tutorial is only a quick introduction to working with Git for the purposes of the course, it’s definitely not a complete guide to Git; we strongly recommend starting to actively use Git for all your projects, not only within the faculty. What you read here will be enough for submitting assignments for the BI-3DT course.
Initial State
For each assignment you’ll have a prepared link that generates a new repository on GitHub. If you don’t have a GitHub account, the server will prompt you to create one. Repositories are generated under the organization 3DprintFIT and are private, which means that only you and the BI-3DT teachers have access to them.
After automatically creating a new repository, you’ll see this:
Installing git
[syky@fedora ~]$ git
bash: git: command not foundAfter installation:
[syky@fedora ~]$ git
usage: git [--version] [--help] [-C <path>] [-c <name>=<value>]
[--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
[-p | --paginate | --no-pager] [--no-replace-objects] [--bare]
[--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
<command> [<args>]
...SSH Key Setup
To communicate with the Git server, you need to ensure your identification, for which an SSH key is used. There is also a username and password option, but we strongly discourage it. GitHub also offers two-factor authentication, which you want to start using.
If you don’t have an SSH key yet
Create it using:
[syky@fedora ~]$ ssh-keygen -t rsa -b 4096You’ll be asked about the key location and passphrase,
it’s entirely up to you what you choose,
the default key path is ~/.ssh/id_rsa and the passphrase can be empty.
The result should look something like this:
Generating public/private rsa key pair.
Enter file in which to save the key (/home/syky/.ssh/id_rsa):
Created directory '/home/syky/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/syky/.ssh/id_rsa.
Your public key has been saved in /home/syky/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:6hIZxGQ2Xmctitvr5D3U+XQv7+B6hZclhJMkLIGHG4U syky@fedora
The key's randomart image is:
+---[RSA 2048]----+
| o= .==+...o |
| +ooEo+ o.+ . |
| ... = o o |
| o o . .|
| = S. . oo|
| + ... o . o.o|
| .oo o ..+ |
| .+... ..o..|
| o+ .. .o.+o|
+----[SHA256]-----+Upozornění:
Never, never, NEVER copy your private key anywhere
(the one that does not end with .pub). Feel free to publish the public key on the web.
If you already have an SSH key (perhaps just created)
Display the public key (the one ending with .pub).
[syky@fedora ~]$ cat ~/.ssh/id_rsa.pubCopy the entire result to the clipboard and go to entering the key on GitHub.
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCiFJ+V+CUF1u1ZRhphaLUU92auMtpJrjWxOMZF8Dqxc6E4cOfWsUNeCLjzeeOT7786DBLBVn60yjEPHcfRcl6hycOJkREpW1WOUTvzMU9nrBde0PTHoB2tV0acWpu+dgyvhMd82VZ6maCojnvvqv99HkQ4wb/HJHAWzTJvHslYXmOiukCxM7zdUaqGkCVvgx8HiCU32Fo3lYkf/7hLs2I8i/P6urNX9ui3vHpeTKXgFHt7vr2U33YcGzkitO8s6KGqWwom29vduXlIWRQMOCLRUTH8OlEm61A0Xful4Xtt1CKSlXDo9TOK6tfEPVI6kKUfCf+2py7glps+wAZ2dy0b syky@fedoraPaste the key into the key field (title is optional) and save.
You’ll see something similar:
Working with the Repository
We recommend creating one folder for your Github repositories for BI-3DT.
[syky@fedora ~]$ mkdir BI-3DT && cd BI-3DTTo clone, use the SSH URL (starts with git@)
and clone the repository to your computer.
Cloning means creating a local copy.
[syky@fedora BI-3DT]$ git clone git@github.com:3DprintFIT/B181AS-Username-syky27.git
Cloning into 'B181AS-Username-syky27'...
The authenticity of host 'github.com (192.30.253.112)' can't be established.
RSA key fingerprint is SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8.
RSA key fingerprint is MD5:16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'github.com,192.30.253.112' (RSA) to the list of known hosts.
remote: Enumerating objects: 4, done.
remote: Counting objects: 100% (4/4), done.
remote: Compressing objects: 100% (4/4), done.
remote: Total 4 (delta 0), reused 4 (delta 0), pack-reused 0
Receiving objects: 100% (4/4), done.
[syky@fedora BI-3DT]$A folder with the repository will be created:
[syky@fedora BI-3DT]$ ll
total 0
drwxrwxr-x. 3 syky syky 54 Sep 28 13:05 B181AS-Username-syky27Inside you’ll find all the files that were in the repository on the server at the time of cloning.
[syky@fedora BI-3DT]$ cd B181AS-Username-syky27
[syky@fedora B181AS-Username-syky27]$ ll
total 8
-rw-rw-r--. 1 syky syky 196 Sep 28 13:05 Jenkinsfile
-rw-rw-r--. 1 syky syky 152 Sep 28 13:05 README.mdDůležité:
If you’re using Git from multiple places
(for example from your computer and from a lab computer)
and you have the repository cloned from before,
always do a pull before starting work to update files,
to avoid conflicts between remote and local changes.
[syky@fedora B181AS-Username-syky27]$ git pull
Already up to date.I’ll create a new file:
[syky@fedora B181AS-Username-syky27]$ echo "My super secret username" > USERNAME
[syky@fedora B181AS-Username-syky27]$ ll
total 12
-rw-rw-r--. 1 syky syky 196 Sep 28 13:05 Jenkinsfile
-rw-rw-r--. 1 syky syky 152 Sep 28 13:05 README.md
-rw-rw-r--. 1 syky syky 25 Sep 28 13:10 USERNAMEGit allows me to look at the changes that have occurred since the last commit:
[syky@fedora B181AS-Username-syky27]$ git status
On branch master
Your branch is up to date with 'origin/master'.
Untracked files:
(use "git add <file>..." to include in what will be committed)
USERNAME
nothing added to commit but untracked files present (use "git add" to track)I see that a new file USERNAME was created, I’ll tell Git
that I want it to track it:
[syky@fedora B181AS-Username-syky27]$ git add USERNAME
[syky@fedora B181AS-Username-syky27]$ git status
On branch master
Your branch is up to date with 'origin/master'.
Changes to be committed:
(use "git reset HEAD <file>..." to unstage)
new file: USERNAMEI’ll describe the change with a commit:
[syky@fedora B181AS-Username-syky27]$ git commit -am"USERNAME file with my username"
*** Please tell me who you are.
Run
git config --global user.email "you@example.com"
git config --global user.name "Your Name"
to set your account's default identity.
Omit --global to set the identity only in this repository.
fatal: unable to auto-detect email address (got 'syky@fedora.(none)')If I see this error, it means I need to tell Git who I am. So:
$ git config --global user.email "sykorto6@fit.cvut.cz"
$ git config --global user.name "Tomáš Sýkora"Then I’ll repeat creating the commit:
[syky@fedora B181AS-Username-syky27]$ git commit -am"USERNAME file with my username"
[master 2078a00] USERNAME file with my username
1 file changed, 1 insertion(+)
create mode 100644 USERNAMEThe commit is created, I can see what changed in it:
[syky@fedora B181AS-Username-syky27]$ git show
commit 2078a007fa2d91e7bc2bb40d802bfa4eb17fd05c (HEAD -> master)
Author: Tomáš Sýkora <sykorto6@fit.cvut.cz>
Date: Fri Sep 28 13:21:39 2018 +0200
USERNAME file with my username
diff --git a/USERNAME b/USERNAME
new file mode 100644
index 0000000..ac11935
--- /dev/null
+++ b/USERNAME
@@ -0,0 +1 @@
+My super secret usernameThen I’ll upload the changes to GitHub:
[syky@fedora B181AS-Username-syky27]$ git push
Warning: Permanently added the RSA host key for IP address '192.30.253.113' to the list of known hosts.
Counting objects: 3, done.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 362 bytes | 362.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To github.com:3DprintFIT/B181AS-Username-syky27.git
dc5189b..2078a00 master -> master
In the repository on the Issues tab you can see the result of our system, which partially automatically evaluates assignments. If you’re done and evaluated (and the task is graded), notify the instructor about points.
