git

Git is a code Version Control System.

Useful resources:

• "Oh shit, git!"
• Git Tips on Github
• Tools for Developers
• /r/git

Sometimes you remember that you have to add a file to the commit you just made.

If you want to add a file to your commit after you already committed the changes:

git add <files>
git commit --amend

This lets you edit the commit description after you committed the changes.

If you don't want to change the commit message: git commit --amend --no-edit

• Learn Git Branching – interactive visual Git tutorial.
• Pro Git book (S. Chacon, B. Straub 2014. Apress)

git config user.name "John Doe"
git config user.email "john@doe.org"

# I want to make sure my master is in sync with the upstream master
git checkout -b merge-patches master
# first pull request
git pull --no-ff https://github.com/user1/repo.git master
# second pull request
git pull --no-ff https://github.com/user2/repo.git branch1

git remote add upstream path/to/repository.git
# get all refs and objects so your git knows what it can do
git fetch --all

You can merge foreign branches:

git merge upstream/master

.git/config

[remote "origin"]
    # add this line
    fetch = +refs/pull/*/head:refs/remotes/origin/pr/*

then execute:

# get refs
git fetch --all
 
# merge pull request with ID 999
git checkout pr/999

(Source)

# change to branch to be added
git checkout master
# push it to the repo
git push -u origin master

Error: [remote rejected] master → master (branch is currently checked out)

# push to new branch on remote
git push origin master:refs/heads/upload
# on remote machine
git merge upload
git branch -d upload

git config --local receive.denyCurrentBranch updateInstead

(source)

If you have two repositories which don't have a common origin, you can still merge them. If you try to do so via simple git pull, you may get the error fatal: refusing to merge unrelated histories. This is because git can't find a commit to base its merge on.

git remote add some-old-repo https://github.com/user/some-old-repo.git
git pull --allow-unrelated-histories some-old-repo master
git status -s

(source)

echo "*" >> ~/.gitignore
git add -f .gitignore

echo "*" >> ~/.gitignore

(Source)

Do a "git diff" on any file. What do you see?

git config core.filemode false

These are the line endings. Automatically adjust it to CRLF line endings with:

git config --global core.autocrlf true

Your permissions may be wrong. Check if any of the remote files in `.git` are not owned by the user you're connecting with. (source)

If you just want to clone a public repo with history from GitHub, don't use the git username like with git clone git@github.com:radicle-dev/radicle-upstream.git, but rather the git:// protocol:

git clone git://github.com/radicle-dev/radicle-upstream.git

Store passwords or other information you don't want to accidentally leak somewhere else than in your git repository.

Use a secrets storage for this. You can use git-secret, blackbox or Hashicorp Vault for this.

Some random articles about how to use Git in a regular or innovative way.

• Beyond Code Control: Git for Everything (A. Schmunk, 2019)
• Git for non-programmers (2014)
• How writers can get work done better with Git (S. Kenlon. Opensource.com, 2019)

• Git vs. GitHub: What's the difference? (2020, Nathan Hekman, IBM Technology)

Useful programs to make life with Git easier or adding functionality to Git.

• ReZip – commit ZIP files to Git.