VCS

Version Control Systems

http://goo.gl/1tc7oh
http://waynelkh.github.io/sa-git

Who am I?

NCTU-CSCC TA

wnlee

What is "verion control"

Version control is a system that records changes to a file or set of files over time so that you can recall specific versions later.

Without Version Control


# 2015-11-10
cp -r project project.bak
# 2015-11-11
cp -r project project.bak1
# 2015-11-12
cp -r project project.bak2
# 2015-11-15
cp -r project project.bak3

Local Version Control Systems

Centralized Version Control Systems

Distributed Version Control Systems

GIT

Distributed Version Control Systems

A Short History of Git

Linus Torvalds (the creator of Linux)
Source Control Management
~2005 BitKeeper
2005~ Git

Git Basic

Snapshots, Not Differences
Nearly Every Operation Is Local
Git Has Integrity
Git Generally Only Adds Data

How to install


                        $ pkg install git

other os

getting started


git config --global user.email "you@example.com"
git config --global user.name "Name"
# global config in ~/.gitconfig

Getting a Git Repository


$ git init
$ git add [file]
$ git commit

The Three States

areas

The lifecycle of the status of your files

lifecycle

.gitignore


# no .a files
*.a
# but do track lib.a, even though you're ignoring .a files above
!lib.a
# only ignore the TODO file in the current directory, not subdir/TODO
/TODO
# ignore all files in the build/ directory
build/
# ignore doc/notes.txt, but not doc/server/arch.txt
doc/*.txt
# ignore all .pdf files in the doc/ directory
doc/**/*.pdf

gitignore.io

git add

Add file contents to the index


$ git add file file1...
$ git add directory
$ git add .

git rm

Add file contents to the index


$ git rm [file]
# only remove files from the index (untrack the file)
$ git rm --cached [file]

git mv

Add file contents to the index


$ git mv file_from file_to 
# equivalent to
$ mv file_from file_to
$ git rm file_from
$ git add file_to

git commit


$ git commit 
-a: stage all modified and deleted path
-m: use the given message as the commit message
--amend: Replace the tip of the current branch by creating a new commit

git status


$ git status -s
M README.md         # updated in index
D run.sh            # deleted from index
R src/main.js       # renamed in index
A src/index.html    # added to index
?? src/READEME.md   # untracked

git log


$ git log
--all
--graph
commit 405251d689b10aba987a081589b334426968e2ac
Author: wnlee wnlee@cs.nctu.edu.tw
Date:   Thu Nov 13 15:22:07 2015 +0800

    Initial commit


$ git log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit
$ git config --global alias.lg "log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --date=relative"

log formats

git diff


git diff [commit] [commit] [file-path]
--cached/--staged
--word-diff

diff

Undoing Things


# Change preview commit again
$ git commit --amend

# Unstaging a Staged File
$ git reset HEAD file

# Unmodifying a Modified File
$ git checkout -- file

git branch

Branching means you diverge from the main line of development and continue to do work without messing with that main line

git branch


# List, create, or delete branches
$ git branch
$ git branch [branch_name]
$ git branch -d [branch_name]

# switch to the branch
$ git checkout [branch name]

# create branch and switch to the branch
$ git checkout -b [branch name]

git merge

merge a branch into your current branch (HEAD)

conflict

Fast-forward
Merge made by the 'recursive' strategy.
Merge conflict

Merge Conflicts

Fix Conflicts
git add
git commit

git rebase

Forward-port local commits to the updated upstream head


# origin
      A---B---C topic (HEAD)
     /
D---E---F---G master

# git rebase master
              A'--B'--C' topic
             /
D---E---F---G master

git rebase -i [commit]