114 lines
3.2 KiB
Markdown
114 lines
3.2 KiB
Markdown
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---
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type: slide
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slideOptions:
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transition: slide
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width: 1400
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height: 900
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margin: 0.1
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---
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<style>
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.reveal strong {
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font-weight: bold;
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color: orange;
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}
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.reveal p {
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text-align: left;
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}
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.reveal section h1 {
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color: orange;
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}
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.reveal section h2 {
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color: orange;
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}
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</style>
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# Introduction to version control
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---
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## Learning goals of section
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- Refresh and organize students' existing knowledge on Git (learn how to learn more).
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- Students can explain difference between merge and rebase and when to use what.
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- How to use Git workflows to organize research software development in a team.
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- Get to know a few useful GitHub/GitLab standards and a few helpful tools.
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---
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## Why do we need version control?
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Version control ...
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- tracks changes to files and helps people share those changes with each other.
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- Could also be done via email / Google Docs / ..., but not as accurately and efficiently
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- was originally developed for software development, but today cornerstone of *reproducible research*
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> "If you can't git diff a file format, it's broken."
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---
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## How does version control work?
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- *master* (or *main*) copy of code in repository, can't edit directly
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- Instead: check out a working copy of code, edit, commit changes back
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- Repository records complete revision history
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- You can go back in time
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- It's clear who did what when
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---
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## The alternative: A story told in file names
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<img src="http://phdcomics.com/comics/archive/phd052810s.gif" width=60% style="margin-left:auto; margin-right:auto">
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[http://phdcomics.com/comics/archive/phd052810s.gif](http://phdcomics.com/comics/archive/phd052810s.gif)
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---
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## A very short history of version control I
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The old centralized variants:
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- 1982: RCS (Revision Control System), operates on single files
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- 1986 (release in 1990): CVS (Concurrent Versions System), front end of RCS, operates on whole projects
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- 1994: VSS (Microsoft Visual SourceSafe)
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- 2000: SVN (Apache Subversion), mostly compatible successor of CVS, *still used today*
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---
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## A very short history of version control II
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Distributed version control:
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- Besides remote master version, also local copy of repository
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- More memory required, but much better performance
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- For a long time: highly fragmented market
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- 2000: BitKeeper (originally proprietary software)
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- 2005: Mercurial
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- 2005: Git
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- A few more
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Learn more: [Podcast All Things Git: History of VC](https://www.allthingsgit.com/episodes/the_history_of_vc_with_eric_sink.html)
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---
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## The only standard today: Git
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No longer a fragmented market, there is nearly only Git today:
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- [Stackoverflow developer survey 2021](https://insights.stackoverflow.com/survey/2021#technology-most-popular-technologies):
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> "Over 90% of respondents use Git, suggesting that it is a fundamental tool to being a developer."
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- All software project candidates for *contribution challenge* use Git
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- Is this good or bad?
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---
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## More facts on Git
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Git itself is open-source: GPL license
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- source on [GitHub](https://github.com/git/git), contributions are a bit more complicated than a simple PR
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- written mainly in C
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- started by Linus Torvalds, core maintainer since later 2005: Junio Hamano
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