Version Control Operations
-  Central repository keeps historical data 
 
-  A commit or check-in adds a change into the repository 
 
-  A pull or update or check-out
retrieves a version from the repository 
 
-  Versions are tracked with version numbers or hashes
	
	-  Numeric or hashes: automatically assigned
 
	-  Symbolic: assigned by humans to track milestones
 
	
 
-  On some VCSs Keywords in the source files are automatically
expanded, identifying version, status, author, etc.