mirror of
https://github.com/m-lamonaca/dev-notes.git
synced 2025-04-05 18:36:41 +00:00
251 lines
11 KiB
Markdown
251 lines
11 KiB
Markdown
# Git
|
|
|
|
## 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 reference 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 <command> -h`: get help for a git command
|
|
`git <command> --help`: get man page for a git command
|
|
`git -C <path> <command>`: execute a git commend in the specified path
|
|
`git <command> <commit>^`: operate on commit *before* the provided commit hash
|
|
|
|
### 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>`: interactively stage chunks of a file
|
|
|
|
`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 commit -v|--verbose`: show unified diff between the HEAD commit and what would be committed
|
|
|
|
`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 <first-branch>...<second-branch>`: show content diff between two branches
|
|
`git diff -w`: show diff ignoring whitespace differences
|
|
|
|
`git bisect`: binary search history (e.g. for regressions)
|
|
|
|
### Stashes
|
|
|
|
`git stash [push -m|--message]`: add all changes to the stash (and provide message)
|
|
`git stash list` list all stashes
|
|
`git stash show [<stash>]`: show changes in the stash
|
|
`git stash pop`: restore last stash
|
|
`git stash drop [<stash>]`: remove a stash from the list
|
|
`git stash clear`: remove all stashes
|
|
|
|
### 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 remote remove <remote>`: remove the specified remote
|
|
`git remote rename <old_name> <new_name>`: rename a remote
|
|
`git branch --set-upstream-to=<remote>/<remote branch>`: set up correspondence between local and remote branch
|
|
|
|
`git push`: send objects to default remote on current 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 push --force`: overwrite remote with local version
|
|
`git push --force-with-lease`: overwrite remote with local version if remote has not been modified
|
|
`git push --force-with-lease --force-if--includes`: will verify if updates from the remote that may have been implicitly updated in the background are integrated locally before allowing a forced update
|
|
|
|
`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 pull --ff`: when possible resolve the merge as a fast-forward (only update branch pointer, don't create merge commit). Otherwise create a merge commit.
|
|
|
|
`git fetch|pull --prune`: remove any remote-tracking references that no longer exist on the remote
|
|
`git fetch|pull --tags`: fetch all tags from the remote
|
|
|
|
`git clone <url> [<folder_name>]`: download repository and repo history from remote
|
|
`git clone --shallow`: clone only repo files, not history of commits
|
|
|
|
> **Note**: for a in depth explanation of `--force-if-includes` see [this][force-if-includes]
|
|
|
|
### 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 shortlog`: list commits by author
|
|
`git reflog`: show record of when the tips of branches and other references were updated in the local repository
|
|
|
|
`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 verified with 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 matching a wildcard 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 -vv`: show branch + last commit + remote status
|
|
`git branch --merged [--remote]`: show branches (remote) that have been merged into current one (needs same history, merge squash/rebase break history)
|
|
|
|
`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 branch -m <old_name> <new_name>`: rename a branch without affecting the branch's history
|
|
|
|
`git merge <branch-name>`: merges into current branch
|
|
`git merge --continue`: continue previous merge after solving a merge conflict
|
|
`git mergetool`: use a fancy tool to help resolve merge conflicts
|
|
`git rebase <branch>`: rebase current branch commits onto another branch
|
|
|
|
`git cherry-pick <commit>`: bring in a commit from another branch
|
|
`git cherry-pick <commit>^..<commit>`: bring in a range of commits from another branch (first included)
|
|
`git cherry-pick <commit>..<commit>`: bring in a range of commits from another branch (first excluded)
|
|
|
|
### Undo & [Rewriting History](https://www.themoderncoder.com/rewriting-git-history/)
|
|
|
|
`git rm -r --cached <file>`: remove a file from being tracked
|
|
`git commit --amend`: replace last commit by creating a new one (can add files or rewrite commit message)
|
|
`git commit --amend -m "amended message"`: 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 reset --soft <commit>`: revert to specific commit but keep changes and staged files
|
|
`git reset --hard <commit>`: discard all history and changes back to specified commit
|
|
|
|
`git checkout <file>`: discard changes
|
|
`git checkout -- <file>`: discard changes, no output to screen
|
|
`git restore .`: discard uncommitted changes
|
|
`git restore <file>`: discard uncommitted changes to file
|
|
`git restore --source <commit> <file>`: revert file to commit version
|
|
`git restore <deleted-file>`: recover deleted file if previously committed
|
|
|
|
`git rebase -i HEAD~<n>`: modify (reword, edit, drop, squash, merge, ...) *n* commits
|
|
`git rebase -i <commit>`: modify (reword, edit, drop, squash, merge, ...) *from* commit to latest
|
|
|
|
> **WARN**: Changing history can have nasty side effects
|
|
|
|
<!-- links -->
|
|
[force-if-includes]: https://stackoverflow.com/a/65839129 "git --force-if-includes explanation"
|