mirror of
https://github.com/m-lamonaca/dev-notes.git
synced 2025-04-07 03:16:41 +00:00
254 lines
9.1 KiB
Markdown
254 lines
9.1 KiB
Markdown
# Git Cheatsheet
|
||
|
||
## Glossary
|
||
|
||
**GIT**: an open source, distributed version-control system
|
||
**GITHUB**: a platform for hosting and collaborating on Git repositories
|
||
|
||
**TREE**: directory that maps names to blobs or trees
|
||
**BLOB**: any file
|
||
**COMMIT**: snapshot of the entire repository + metadata, identified it's SHA-1 hash
|
||
|
||
**HEAD**: represents the current working directory, the HEAD pointer can be moved to different branches, tags, or commits when using git checkout
|
||
**BRANCH**: a lightweight movable pointer to a commit
|
||
**CLONE**: a local version of a repository, including all commits and branches
|
||
**REMOTE**: a common repository on GitHub that all team member use to exchange their changes
|
||
|
||
**FORK**: a copy of a repository on GitHub owned by a different user
|
||
**PULL REQUEST**: a place to compare and discuss the differences introduced on a branch with reviews, comments, integrated tests, and more
|
||
|
||
**REPOSITORY**: collection of files and folder of a project aka repo
|
||
**STAGING AREA/STASH**: area of temporary snapshots (not yet commits)
|
||
|
||
## Data Model
|
||
|
||
Data Model Structure:
|
||
|
||
```txt
|
||
<root> (tree)
|
||
|
|
||
|_ foo (tree)
|
||
| |_ bar.txt (blob, contents = "hello world")
|
||
|
|
||
|_ baz.txt (blob, contents = "git is wonderful")
|
||
```
|
||
|
||
Data Model as pseudocode:
|
||
|
||
```py
|
||
# a file is a bunch of bytes
|
||
blob = array<byte>
|
||
|
||
# a directory contains named files and directories
|
||
tree = map<string, tree | file>
|
||
|
||
# a commit has parents, metadata, and the top-level tree
|
||
commit = struct {
|
||
parent: array<commit>
|
||
author: string
|
||
message: string
|
||
snapshot: tree
|
||
}
|
||
|
||
# an object is either a blob, tree or commit
|
||
object = map<string, blob | tree | commit>
|
||
|
||
# commit identified by it's hash (unmutable)
|
||
def store(object):
|
||
id = sha1(object) # hash repo
|
||
objects<id> = object # store repo w/ index hash
|
||
|
||
# load the commit
|
||
def load(id):
|
||
return objects<id>
|
||
|
||
# human-readable names for SHA-1 hashes (mutable)
|
||
references = map<string, string>
|
||
|
||
# bind a regerence to a hash
|
||
def update_reference(name, id):
|
||
references<name> = id
|
||
|
||
def read_reference(name):
|
||
return references<name>
|
||
|
||
def load_reference(name_or_id):
|
||
if name_or_id in references:
|
||
return load(references<name_or_id>)
|
||
else:
|
||
return load(name_or_id)
|
||
```
|
||
|
||
## Commands
|
||
|
||
`git help <command>`: get help for a git command
|
||
|
||
### Create Repository
|
||
|
||
`git init [<project_name>]`: initialize a brand new Git repository and begins tracking
|
||
`.gitignore`: specify intentionally untracked files to ignore
|
||
|
||
### Config
|
||
|
||
`git config --global user.name "<name>"`: set name attached to commits
|
||
`git config --global user.email "<email address>"`: set email attached to commits
|
||
`git config --global color.ui auto`: enable colorization of command line output
|
||
|
||
### Making Changes
|
||
|
||
`git status`: shows the status of changes as untracked, modified, or staged
|
||
`git add <filename1 filename2 ...>`: add files to the staging area
|
||
`git add -p <files>`: interacively stage chuncks of a file
|
||
|
||
`git stash`: temporarily remove modifications to working directory (must be staged to be stashed)
|
||
`git stash pop`: recuperate stashed changes
|
||
|
||
`git blame <file>`: show who last edited which line
|
||
|
||
`git commit`: save the snapshot to the project history
|
||
`git commit -m "message"`: commit and provide a message
|
||
`git commit -a`: automatically notice any modified (but not new) files and commit
|
||
|
||
`git diff <filename>`: show difference since the last commit
|
||
`git diff <commit> <filename>`: show differences in a file since a particular snapshot
|
||
`git diff <reference_1> <reference_2> <filename>`: show differences in a file between two snapshots
|
||
`git diff --cached`: show what is about to be committed
|
||
`git diff <firts-branch>...<second-branch>`: show content diff between two branches
|
||
|
||
`git bisect`: binary search history (e.g. for regressions)
|
||
|
||
### Remotes
|
||
|
||
`git remote`: list remotes
|
||
`git remote -v`: list remotes names and URLs
|
||
`git remote show <remote>`: inspect the remote
|
||
|
||
`git remote add <remote> <url | path>`: add a remote
|
||
`git branch --set-upstream-to=<remote>/<remote branch>`: set up correspondence between local and remote branch
|
||
|
||
`git push <remote> <branch>`: send objects to remote
|
||
`git push <remote> <local branch>:<remote branch>`: send objects to remote, and update remote reference
|
||
|
||
`git fetch [<remote>]`: retrieve objects/references from a remote
|
||
`git pull`: update the local branch with updates from its remote counterpart, same as `git fetch; git merge`
|
||
|
||
`git fetch && git show <remote>/<branch>`: show incoming changes
|
||
|
||
`git clone <url> [<folder_name>]`: download repository and repo history from remote
|
||
`git clone --shallow`: clone only repo files, not history of commits
|
||
|
||
`git remote remove <remote>`: remove the specified remote
|
||
`git remote rename <old_name> <new_name>`: rename a remote
|
||
|
||
### Viewing Project History
|
||
|
||
`git log`: show history of changes
|
||
`git log -p`: show history of changes and complete differences
|
||
`git log --stat --summary`: show overview of the change
|
||
`git log --follow <file>`: list version history fo file, including renames
|
||
`git log --all --graph --decorate`: visualizes history as a DAG
|
||
`git log --oneline`: compact log
|
||
|
||
`git show <commit>`: output metadata and content changes of commit
|
||
`git cat-file -p <commit>`: output commit metadata
|
||
|
||
### Tag
|
||
|
||
Git supports two types of tags: *lightweight* and *annotated*.
|
||
|
||
A lightweight tag is very much like a branch that doesn’t change—it’s just a pointer to a specific commit.
|
||
|
||
Annotated tags, however, are stored as full objects in the Git database.
|
||
They’re checksummed;contain the tagger name, email, and date; have a tagging message; and can be signed and verifiedwith GNU Privacy Guard (GPG).
|
||
It’s generally recommended creating annotated tags so it's possible to have all this information.
|
||
|
||
`git tag`: list existing tags
|
||
`git tag -l|--list <pattern>`: list existing tags mathcing a wildard or pattern
|
||
|
||
`git tag <tag> [<commit_hash>]`: create a *lightweight* tag on the commit
|
||
`git tag -a <tag> [<commit_hash> -m <message>]`: create am *annotated* tag on the commit
|
||
|
||
`git push <remote> <tagname>`: push a tag to the remote
|
||
`git push <remote> --tags`: push commits and their tags (both types) to the remote
|
||
|
||
`git tag -d <tagname>`: delete a tag
|
||
`git push <remote> :refs/tags<tagname>:`: remove a tag from the remote
|
||
`git push <remote> --delete <tagname>`: remove a tag from the remote
|
||
|
||
`git checkout <tag>`: checkout a tag - **WARNING**: will go into *detached HEAD*
|
||
|
||
### Branching And Merging
|
||
|
||
`git branch`: shows branches
|
||
`git branch -v`: show branch + last commit
|
||
|
||
`git branch <branch-name>`: create new branch
|
||
`git checkout -b <branch-name>`: create a branch and switches to it, same as `git branch <name>; git checkout <name>`
|
||
`git branch`: show list of all existing branches (* indicates current)
|
||
`git checkout <branch-name>`: change current branch (update HEAD) and update working directory
|
||
`git branch -d <branch-name>`: delete specified branch
|
||
|
||
`git merge <branch-name>`: merges into current branch
|
||
`git merge --continue`: continue previous merge after solving a merge conflinct
|
||
`git mergetool`: use a fancy tool to help resolve merge conflicts
|
||
`git rebase`: rebase set of patches onto a new base
|
||
`git rebase -i`: interactive rebasing
|
||
|
||
`gitk`: show graph of history (git for windows only)
|
||
|
||
### Undo & [Rewriting History](https://www.themoderncoder.com/rewriting-git-history/)
|
||
|
||
`git commit --amend`: replace last commit by creating a new one (can add files or rewrite commit message)
|
||
`git commit --amend --no-edit`: replace last commit by creating a new one (can add files or rewrite commit message)
|
||
`git reset HEAD <file>`: unstage a file
|
||
`git reset <commit>`: undo all commits after specified commit, preserving changes locally
|
||
`git checkout <file>`: discard changes
|
||
`git checkout -- <file>`: discard changes, no output to screen
|
||
`git reset --hard`: discard all changes since last commit
|
||
`git reset --hard <commit>`: discard all history and changes back to specified commit
|
||
`git rebase -i HEAD~<n>`: modify (reword, edit, drop, squash, merge, ...) *n* commits
|
||
|
||
**WARNING**: Changing history can have nasty side effects
|
||
|
||
---
|
||
|
||
## How To
|
||
|
||
### Rebase Branches
|
||
|
||
```ps1
|
||
git checkout <primary_branch>
|
||
git pull # get up to date
|
||
|
||
git checkout <feature_branch>
|
||
git rebase <primary_branch> # rebase commits on master (moves branch start point on last master commit)
|
||
|
||
git chechout <primary_branch>
|
||
git rebase <feature_branch> # moves commits from the branch on top of master
|
||
```
|
||
|
||
|
||
|
||
### Clone Branches
|
||
|
||
```ps1
|
||
git clone <repo> # clone the repo
|
||
|
||
git branch -r # show remote branches
|
||
git checkout <branch> # checkout remote branch (omit <remote>/)
|
||
|
||
git pull # clone branch
|
||
```
|
||
|
||
### [Sync Forks][github sync frok guide]
|
||
|
||
[github sync frok guide](https://docs.github.com/en/free-pro-team@latest/github/collaborating-with-issues-and-pull-requests/syncing-a-fork)
|
||
|
||
```ps1
|
||
git fetch upstream # Fetch the branches and their respective commits from the upstream repository
|
||
git checkout main # chechout fork's main primary branch
|
||
|
||
git merge upstream/main # Merge the changes from the upstream default branch into the local default branch
|
||
|
||
git push # update fork on GitHub
|
||
```
|