| layout | title | permalink | resource |
|---|---|---|---|
page |
Git |
/git/ |
true |
- Access
- Branch out of sync with master
- Setup Workflow
- SSH Keys
- Test key-account auth
- Cloning
- Multiple SSH keys for different accounts
- Resources
The Git protocol was created by Linus Torvalds. He also created the original Linux kernel.
repo, https://github.com/gmcmillan100/docs
pages, https://gmcmillan100.github.io/docs/
Test ssh access:
$ ssh -T [email protected]
Hi gmcmillan100! You've successfully authenticated, but GitHub does not provide shell access.
Do this to bring the lastest changes in master into your local Git branch:
git checkout master git pull git checkout git rebase master
Global config:
git config --global user.email "[email protected]"
git config --global user.name "Greg McMillan"
Verify the global .gitconfig looks correct:
$ cat .gitconfig
# This is Git's per-user configuration file.
[user]
name = gmcmillan100
email = [email protected]
Initialize repo and pull down a copy:
mkdir docs
cd docs
git init .
git remote add origin [email protected]:gmcmillan100/docs.git
cat .git/config
git pull [email protected]:gmcmillan100/docs.git master
Push the current branch and set the remote as upstream:
git fetch
git branch --set-upstream-to=origin/master master
Upload some changes:
git add git.md
git commit -m "initial commit"
git pull --rebase
git push
Main article: https://help.github.com/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent/#platform-linux
Generate a new ssh key:
$ ssh-keygen -t rsa -b 4096 -C "[email protected]"
Generating public/private rsa key pair.
Enter file in which to save the key (/home/greg/.ssh/id_rsa): Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/greg/.ssh/id_rsa.
Your public key has been saved in /home/greg/.ssh/id_rsa.pub.
The key fingerprint is:
ef:63:96:f2:47:90:76:69:27:ab:62:9b:d9:df:67:ea [email protected]
The key's randomart image is:
+--[ RSA 4096]----+
| |
| |
| . . |
| + = . |
| S. + + |
| . o |
| .+ |
| +=* .. o|
| .+B++..E+ |
+-----------------+
Display existing key files:
$ ls -al ~/.ssh
total 20
drwx------ 2 greg greg 512 Jan 2 15:27 .
drwxr-xr-x 4 greg greg 512 Jan 1 07:12 ..
-rw------- 1 greg greg 3326 Jan 2 15:27 id_rsa
-rw-r--r-- 1 greg greg 748 Jan 2 15:27 id_rsa.pub
-rw-r--r-- 1 greg greg 1014 Jan 2 15:17 known_hosts
Start the ssh-agent and add the new key:
$ eval "$(ssh-agent -s)"
Agent pid 1034
$ ssh-add ~/.ssh/id_rsa
Enter passphrase for /home/greg/.ssh/id_rsa:
Identity added: /home/greg/.ssh/id_rsa (/home/greg/.ssh/id_rsa)
Display the new public key:
$ cat ~/.ssh/id_rsa.pub
ssh-rsa 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 [email protected]
After adding the key to github.com > settings, verify Github can see the key-account mapping from my local host:
$ ssh -T [email protected]
Hi gmcmillan100! You've successfully authenticated, but GitHub does not provide shell access.
Can also use -i for more control:
$ ssh -i ~/.ssh/id_rsa -o IdentityAgent=none -T [email protected]
Hi gmcmillan100! You've successfully authenticated, but GitHub does not provide shell access.
and notice how this key produces a different user response:
$ ssh -i ~/.ssh/gmcmilla_at_linkedin.com_ssh_key -o IdentityAgent=none -T [email protected]
Hi gmcmilla_LinkedIn! You've successfully authenticated, but GitHub does not provide shell access.
git clone [email protected]:gmcmillan100/docs.git
Problem. During a git push in my personal docs repo, git was using my work ssh key and user identity. My personal key identity was not being used, resulting in no access.
$ cd /Users/gmcmilla/docs
$ git push
ERROR: Permission to gmcmillan100/docs.git denied to gmcmilla_LinkedIn.
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
But outside of git push and the repo, my personal ssh key could authenticate with github.com when the key file is read directly:
$ cd ~
$ ssh -i ~/.ssh/id_rsa -o IdentityAgent=none -T [email protected]
Hi gmcmillan100! You've successfully authenticated, but GitHub does not provide shell access.
ssh -vv revealed that only my work SSH key was being used:
$ ssh -vv -T [email protected]
OpenSSH_9.4p1, LibreSSL 3.3.6
...
debug1: identity file /Users/gmcmilla/.ssh/gmcmilla_at_linkedin.com_ssh_key type 0
debug1: identity file /Users/gmcmilla/.ssh/gmcmilla_at_linkedin.com_ssh_key-cert type -1
and IdentityFile was set to my work ssh key everywhere in ~/.ssh/config:
$ cat ~/.ssh/config
...
Match host github.com user org-132020358,org-132020684,org-132020707,org-127256988,org-132020694,org-127349224
ProxyCommand none
IdentityFile %d/.ssh/%u_at_linkedin.com_ssh_key
Solution. Create an alias for my personal ssh key for my personal GitHub repo, so it does not conflict with work's ssh key.
Article: How do I configure git to use multiple SSH keys for different accounts
-
Before I do anything, ensure my private id_rsa key is added to the keychain:
$ ssh-add ~/.ssh/id_rsa Enter passphrase for /Users/gmcmilla/.ssh/id_rsa: Identity added: /Users/gmcmilla/.ssh/id_rsa ([email protected]) $ ssh-add -l 4096 SHA256:fqqsrkCl6ak0zhG1nAUCt9NYX4yJcqc3Wq1gymcLPpE [email protected] (RSA) -
Create a custom ssh config file. LinkedIn does not allow me to edit
~/.ssh/config, so all customizations must go in a separate custom file.touch ~/.ssh/config.custom vi ~/.ssh/config.custom -
Add a github alias (named
github-personal) that points to my personal SSH key IdentityFile at~/.ssh/id_rsa:Host github-personal IdentityFile ~/.ssh/id_rsa User git HostName github.com UseKeychain yesThe user must be
git, and the HostName must begithub.com. -
Identify the origin setting inside my personal repo.
To see which remote servers you have configured, run the
git remotecommand. It lists the shortnames of each remote handle you’ve specified. If you’ve cloned your repository, you should at least seeorigin. That is the default name Git gives to the server you cloned from:$ cd /Users/gmcmilla/docs $ git remote originYou can also specify
-v, which shows you the URLs that Git has stored for the shortname to be used when reading and writing to that remote:$ git remote -v origin [email protected]:gmcmillan100/docs.git (fetch) origin [email protected]:gmcmillan100/docs.git (push)In Git,
originis a shorthand name for the remote repository that a project was originally cloned from. More precisely, it is used instead of that original repository's URL - and thereby makes referencing much easier. Remotes are simply an alias that store the URL of repositories. You can see what URL belongs to each remote by usinggit remote -v. -
Change the remote origin to use the new SSH alias:
$ git remote set-url "origin" "github-personal:gmcmillan100/docs.git"Verify it changed:
$ git remote -v origin github-personal:gmcmillan100/docs.git (fetch) origin github-personal:gmcmillan100/docs.git (push)The next time I
git push, the alias will be used (seegithub-personal):$ git push Enumerating objects: 5, done. Counting objects: 100% (5/5), done. Delta compression using up to 16 threads Compressing objects: 100% (3/3), done. Writing objects: 100% (3/3), 933 bytes | 933.00 KiB/s, done. Total 3 (delta 2), reused 0 (delta 0), pack-reused 0 remote: Resolving deltas: 100% (2/2), completed with 2 local objects. To github-personal:gmcmillan100/docs.git c1e5cd9..99d1978 master -> master -
Troubleshooting no identity and no keychain
During a
git push, I noticed my work permissions reverted and started overriding my personal account again:$ git push ERROR: Permission to gmcmillan100/docs.git denied to gmcmilla_LinkedIn. fatal: Could not read from remote repository.There was no personal id_rsa key identity in my keychain. It got lost somehow. Maybe LinkedIn SysOps reset it.
$ ssh-add -l The agent has no identities.So I added it back in:
$ ssh-add ~/.ssh/id_rsa Enter passphrase for /Users/gmcmilla/.ssh/id_rsa: Identity added: /Users/gmcmilla/.ssh/id_rsa ([email protected]) $ ssh-add -l 4096 SHA256:fqqsrkCl6ak0zhG1nAUCt9NYX4yJcqc3Wq1gymcLPpE [email protected] (RSA)Then,
git pushin mydocsrepo began working again:$ cd docs $ git push Enumerating objects: 7, done. Counting objects: 100% (7/7), done. Delta compression using up to 16 threads Compressing objects: 100% (4/4), done. Writing objects: 100% (4/4), 806 bytes | 806.00 KiB/s, done. Total 4 (delta 3), reused 0 (delta 0), pack-reused 0 remote: Resolving deltas: 100% (3/3), completed with 3 local objects. To github-personal:gmcmillan100/docs.git 5b35e52..acac7c6 master -> masterIf it's still not working, remove the identities and re-add:
$ ssh-add -D All identities removed. $ ssh-add -l The agent has no identities. $ ssh-add ~/.ssh/id_rsa
GitHub Pages, https://pages.github.com/
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