Version Control

Version Control

• Keeping track of versions and changes
• Know who changed what
• Handle conflicting changes

Similar to:

• Saving files with different names
  • But automatic
  • And better for searching
  • Each "version" can have comments and information
  • VC can handle multiple files at once
• Online document sharing
  • But VC is not simultaneous, user specifies when to share
  • This makes sense for code which must be "complete" before sharing

Good for:

• Text files
• Code files
• Small program resources (that don't change often)
  • e.g. program icon files

Bad for:

• Binary formats
  • e.g. Word documents, PDF
  • Any small change in a binary file will usually cause the whole file to be marked as changed, which can lead to a very large and inefficient repsotory
• Large data files
  • Specially if they change often or significantly

Concepts

• Repository
  • The "place" where the files are stored
  • Often a web address from which the files can be accessed
  • Often abbreviated as "repo"
• Client software
  • VC requires special software to download and upload changes

More concepts

• Fork
  • A new independent copy of a repository
• Branch
  • An independent specific "version" of a repo, usually to implement specific functionality (before actually have the other collaborators use it by default)

More Concepts

• Merge
  • Bring the changes from others together with your own
• Conflict
  • What happens when you and someone else have modified some file in the same place

Version control systems

• CVS (Concurrent Version System)
• SVN (SubVersioN)
• Git
• Many others:
  • Bazaar, Mercurial, etc.

Distributed VC

• More common one today
• Does not rely on a central server
  • There can be one, but it doesn't have more "power" than any of the other peers
• All copies of the repository are (almost) identical.
  • They all have all versions
  • And they can have all branches (although under certain circumstances they don't...)

Git commands

• Commit
  • Set a revision
  • The changes are stored as a single "unit"
  • Done only on the local repo
• Push/Pull
  • Send/receive changes from a remote repo

Websites offering git hosting

www.github.com

www.bitbucket.com

many others...