Version Control Systems

Transcription

1 Version Control Systems How to share files with others in an efficient, safe and easy way C. Carouge, N. Haughton, A. Hotz, L. Fita Climate Change Research Centre, UNSW Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 1 / 18

2 Outline 1 Who needs Version Control? 2 What is a Version Control System? How do VCSs work? Centralised vs Distributed VCS 3 GIT: Basic Use Getting Started and Updating Adding your changes Branching, tagging and merging Cool features 4 Graphical interfaces 5 Best Practice 6 Online Hosting 7 Tutorials and Questions Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 2 / 18

3 Who needs Version Control? Sharing files can get messy... A team is working in the same project and they are sharing the same files Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 3 / 18

4 Who needs Version Control? Sharing files can get messy... A team is working in the same project and they are sharing the same files They start to use different names, write names of the files with date, names,... atmosphere_ f90 atmosphere_ f90 atmosphere_ f90 atmosphere_john.f90 Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 3 / 18

5 Who needs Version Control? Sharing files can get messy... A team is working in the same project and they are sharing the same files They start to use different names, write names of the files with date, names,... atmosphere_ f90 atmosphere_ f90 atmosphere_ f90 atmosphere_john.f90 Or they start to open directories for each version: John_v2/ Adela_cloud Julius_landsurf_changes/ Julius_soil_test/ Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 3 / 18

6 Who needs Version Control? Sharing files can get messy... Eventually no one knows which is the correct version, or which one was the last working one... Someone accidentally ran rm -rf * instead of rm -rf *.temp. And the backups are out of date. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 4 / 18

7 Who needs Version Control? Sharing files can get messy... Eventually no one knows which is the correct version, or which one was the last working one... Someone accidentally ran rm -rf * instead of rm -rf *.temp. And the backups are out of date. A version control system could really help here! Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 4 / 18

8 What is a Version Control System? What is a Version Control System? Tool for keeping track of changes to files. Allows easy sharing of projects between users. Allows different users to edit a file at the same time, and handles conflicts. Allows different versions of projects to be used and worked on concurrently. arouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 5 / 18

9 What is a Version Control System? What is a Version Control System? Tool for keeping track of changes to files. Allows easy sharing of projects between users. Allows different users to edit a file at the same time, and handles conflicts. Allows different versions of projects to be used and worked on concurrently. Many different options: Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 5 / 18

10 What is a Version Control System? How do VCSs work? How do VCSs work? A VCS consists of: A repository that keeps track of changes to a set of files (may be local or on a server). Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 6 / 18

11 What is a Version Control System? How do VCSs work? How do VCSs work? A VCS consists of: A repository that keeps track of changes to a set of files (may be local or on a server). A working directory that contains a copy of files in the repository, for editing. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 6 / 18

12 What is a Version Control System? How do VCSs work? How do VCSs work? A VCS consists of: A repository that keeps track of changes to a set of files (may be local or on a server). A working directory that contains a copy of files in the repository, for editing. The software used to record (or commit) the changes in the working directory to the repository. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 6 / 18

13 What is a Version Control System? How do VCSs work? How do VCSs work? A VCS consists of: A repository that keeps track of changes to a set of files (may be local or on a server). A working directory that contains a copy of files in the repository, for editing. The software used to record (or commit) the changes in the working directory to the repository. The VCS allows the user to: Review the history of changes from all collaborators. Revert to a previous version of the work (e.g. testing purposes). Branch from any point from the history for parallel development. Merge changes from different branches back together. Easily, quickly, and reliably update copies on several machines. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 6 / 18

14 What is a Version Control System? How do VCSs work? Example: How do VCSs work? John_dev 1 2 Adele_atmos 4 Tag: version 0.9 master Tag: version Julius_soil 6 1. John makes his changes and commits them. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 7 / 18

15 What is a Version Control System? How do VCSs work? Example: How do VCSs work? John_dev 1 2 Adele_atmos 4 Tag: version 0.9 master Tag: version Julius_soil 6 1. John makes his changes and commits them. 2. Adele pulls John s code and starts working on it. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 7 / 18

16 What is a Version Control System? How do VCSs work? Example: How do VCSs work? John_dev 1 2 Adele_atmos 4 Tag: version 0.9 master Tag: version Julius_soil 6 1. John makes his changes and commits them. 2. Adele pulls John s code and starts working on it. 3. At the same time Julius clones the repository for the first time, and starts working on it. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 7 / 18

17 What is a Version Control System? How do VCSs work? Example: How do VCSs work? John_dev 1 2 Adele_atmos 4 Tag: version 0.9 master Tag: version Julius_soil 6 1. John makes his changes and commits them. 2. Adele pulls John s code and starts working on it. 3. At the same time Julius clones the repository for the first time, and starts working on it. 4. Adele commits and pushes her changes in the cloud subroutine. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 7 / 18

18 What is a Version Control System? How do VCSs work? Example: How do VCSs work? John_dev 1 2 Adele_atmos 4 Tag: version 0.9 master Tag: version Julius_soil 6 1. John makes his changes and commits them. 2. Adele pulls John s code and starts working on it. 3. At the same time Julius clones the repository for the first time, and starts working on it. 4. Adele commits and pushes her changes in the cloud subroutine. 5. Julius pulls Adele s changes, and merges (6) his changes in the soil subroutine with the rest of the code. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 7 / 18

19 What is a Version Control System? Centralised vs Distributed VCS Centralised vs Distributed VCS Two main paradigms: Centralised Distributed Repository (on network) Repository (on network) John's Repository Adele's working copy John's working copy Julius' working copy Adele's Repository Adele's working copy Julius' Repository Julius' working copy e.g. CVS, SVN e.g. Git, Mercurial, Bazaar Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 8 / 18

20 What is a Version Control System? Centralised vs Distributed VCS DVCS benefits Can use DVCS while off-line, then upload all commits when online. Every repository has the full history: automatic redundant backups. Generally much faster, because most operations are done locally. Reliable merging. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 9 / 18

21 Getting Started GIT: Basic Use Getting Started and Updating Starting from scratch: starts a repository from the current folder git init Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 10 / 18

22 Getting Started GIT: Basic Use Getting Started and Updating Starting from scratch: starts a repository from the current folder git init Getting the repository: copies an entire repository, and sets it as the default remote repository ( origin ) [equivalent to [svn cvs] checkout <repository> ]. git clone <repository> e.g.: clone from a webserver: git clone e.g.: clone from ssh: git clone user@server.org:/path/to/repository Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 10 / 18

23 GIT: Basic Use Getting Started and Updating Updating Updating: Update your clone from the origin [equivalent to [svn cvs] update ] git fetch, git merge git pull Seeing changes: See what has changed since last time git log Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 11 / 18

24 Adding your changes GIT: Basic Use Adding your changes 1. Make sure to git pull before making changes! Saves work later. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 12 / 18

25 Adding your changes GIT: Basic Use Adding your changes 1. Make sure to git pull before making changes! Saves work later. 2. checking: git status to see what changes are in the working copy. git diff [files] to see how your working copy differs from the last commit. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 12 / 18

26 Adding your changes GIT: Basic Use Adding your changes 1. Make sure to git pull before making changes! Saves work later. 2. checking: git status to see what changes are in the working copy. git diff [files] to see how your working copy differs from the last commit. 3. marking files: After making changes select files to commit. git add <files> Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 12 / 18

27 Adding your changes GIT: Basic Use Adding your changes 1. Make sure to git pull before making changes! Saves work later. 2. checking: git status to see what changes are in the working copy. git diff [files] to see how your working copy differs from the last commit. 3. marking files: After making changes select files to commit. git add <files> 4. committing and comment: commit the changes to the repository. Always describe what have you changed! This won t add unmarked changes from the working copy to the repository. git commit -m commit message Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 12 / 18

28 Adding your changes GIT: Basic Use Adding your changes 1. Make sure to git pull before making changes! Saves work later. 2. checking: git status to see what changes are in the working copy. git diff [files] to see how your working copy differs from the last commit. 3. marking files: After making changes select files to commit. git add <files> 4. committing and comment: commit the changes to the repository. Always describe what have you changed! This won t add unmarked changes from the working copy to the repository. git commit -m commit message 5. sending changes: push your commits to remote server. git push Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 12 / 18

29 GIT: Basic Use Branching, tagging and merging Branching, tagging and merging new_soil new_dataset cloud_bug master Branches are for new experimental features, or alternative implementations. They allow simultaneous changes. Tags are for marking commits as special. Useful for highlighting versions of the code. Merging allows modifications from different branches to be combined. Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 13 / 18

30 GIT: Basic Use Cool features Cool features use git as a front-end for svn. Creates a local git repo, and automatically handles committing/pushing. git svn clone <svn-repository> Add a.gitignore file to tell git to ignore certain file types, like L A TEX auxiliary files. See changes word-by-word, instead of line-by-line. Great for L A TEX. git diff --word-diff [file] Find out who was the last to modify the given lines. git blame -L <start>,<end> <file> Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 14 / 18

31 Graphical interfaces Graphical interfaces Many GUIs available: Cross-platform: GitK, Git-GUI (distributed with Git) Linux: Git-Cola, Giggle OSX: GitX Windows: Tortoise-Git Allow to do almost all operations without knowing the command line options Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 15 / 18

32 Best Practice Best Practice Check changes before committing. Check commits before pushing. See also: Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 16 / 18

33 Best Practice Best Practice Check changes before committing. Check commits before pushing. All commits should have a descriptive commit message. See also: Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 16 / 18

34 Best Practice Best Practice Check changes before committing. Check commits before pushing. All commits should have a descriptive commit message. Commit Early, Commit Often: Small commits make it easier to see what changes are being made. Individual commits can easily be merged into other branches. See also: Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 16 / 18

35 Best Practice Best Practice Check changes before committing. Check commits before pushing. All commits should have a descriptive commit message. Commit Early, Commit Often: Small commits make it easier to see what changes are being made. Individual commits can easily be merged into other branches. Push and pull regularly Helps others keep track of what changes you re making. Make sure you re up to date before making changes. See also: Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 16 / 18

36 Best Practice Best Practice Check changes before committing. Check commits before pushing. All commits should have a descriptive commit message. Commit Early, Commit Often: Small commits make it easier to see what changes are being made. Individual commits can easily be merged into other branches. Push and pull regularly Helps others keep track of what changes you re making. Make sure you re up to date before making changes. Use Development branches for work in progress code. Small, self-contained branches are easier to merge. See also: Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 16 / 18

37 Best Practice Best Practice Check changes before committing. Check commits before pushing. All commits should have a descriptive commit message. Commit Early, Commit Often: Small commits make it easier to see what changes are being made. Individual commits can easily be merged into other branches. Push and pull regularly Helps others keep track of what changes you re making. Make sure you re up to date before making changes. Use Development branches for work in progress code. Small, self-contained branches are easier to merge. Merge into master branch only when it works. See also: Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 16 / 18

38 Online Hosting Online Hosting Why host your repository online? Invite others to connect to your repository via . View commits and merges graphically using the browser. Offsite backup. Where can you host online? Bitbucket (free unlimited account for academics): Github (free for open source): Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 17 / 18

39 Tutorials and Questions Tutorials Git tutorial: Git tutorial (for SVN users): Mercurial tutorial: For all: Google! arouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 18 / 18

40 Tutorials and Questions Tutorials Git tutorial: Git tutorial (for SVN users): Mercurial tutorial: For all: Google! Questions? Carouge, Haughton, Hotz, Fita (CCRC, UNSW) Version Control Systems 18 / 18