Old Versioning Systems

Note: Delta storage systems get slower as more revisions happen.

Note: sequencing version number

New Versioning Systems

A file can have a SHA-1 HASH code (40 character Hex code).

A GIT tree is a DAG (directed acyclical graph)

HEAD - the current branch head

HEAD^3 - go back 3 commits

git log   <- shows history

git log --pretty=oneline

git log HEAD^^^..HEAD

git show

git -a -m'This is  an add and a commit'