Introduction to the Git version control system and the Git repository hosting service Github.

1. An Introduction
By Christopher Pezza – Monfort College of Business 2012

2.  Version Control refers to
management of changes
to documents, programs,
large web sites and other
information stored as
computer files.
 Used in software
development, where a
team of people may
change the same files.
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3.  git /'ɡɪt/ -- Git is an
extremely
fast, efficient, distributed
version control system
ideal for the collaborative
development of software.
 Invented by Linus Torvalds
 Version Control Tool
 Powerful
 Flexible
 Low-Overhead
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5.  Facilitate Distributed
Development
 Scale to handle thousands of
developers
 Perform quickly and
efficiently
 Maintain integrity and trust
 Enforce accountability
 Immutability
 Atomic transactions
 Support and encourage
branched development
 Complete repositories
 A clean internal design
 Be free, as in freedom
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6.  Allow parallel as well as
independent and
simultaneous
development in private
repositories without the
need for constant
synchronization with a
central repository
 Allow multiple developers
in multiple locations even
if some of them are offline
temporarily
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7.  Thousands of developers
contribute to each Linux
release
 Handle a very large
number of
developers, whether they
are working on the same
or on different parts of a
common project
 VCS must integrate all
work reliably
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8.  Needs to support a large
volume of update
operations that would be
made on the Linux Kernel
 Individual update
operations and network
transfer operations have
to be very fast
 To save space and thus
transfer
time, compression and
“delta” techniques would
be needed
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9.  Git uses a common
cryptographic hash
function, called SHA1, to
name and identify objects
within its database
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10.  Git enforces a change log
on every commit that
changes a file
 Git ensures that changes
will not happen
mysteriously to files under
version control because
there is an accountability
trail for all changes.
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11.  Once objects have been
created and placed in the
database, they cannot be
modified
 Objects can be recreated
differently, but the
original data cannot be
altered.
 The entire history stored
within the version control
database is also
immutable.
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12.  A number of different but
related changes are
performed either all
together or not at all
 Ensures that the version
control database is not
left in a partially changed
(possibly corrupted) state
while an update or
commit is happening
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13.  VCSs can name different
genealogies of
development within a
single project
 VCS can also split a single
line of development into
multiple lines and then
unify, or merge, the
disparate threads
 Git calls a line of
development a branch
and assigns each branch a
name
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14.  In order to avoid
individual developers
needing to query a
centralized repository
server for historical
revision information, each
repository has a complete
copy of all historical
revisions of every file.
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15.  Git’s object model has
simple structures that
capture fundamental
concepts for raw data,
directory structure,
recording changes, etc.
 Coupling the object model
with a globally unique
identifier technique
allowed a very clean data
model that could be
managed in a distributed
development
environment.
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16.  “Free software” means
software that respects
users' freedom and
community.
 users have the freedom
to
run, copy, distribute, stud
y, change and improve
the software
 Free Software is a matter
of liberty, not price: Think
“free” as in “free speech,”
not as in “free beer”.
 Example: GNU Licenses
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19.  social networking
functionality such as
feeds, followers and the
network graph to display
how developers work on
their versions of a
repository.
 a pastebin-style site called
Gist
 wikis for individual
repositories
 web pages that can be
edited through a Git
repository
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23.  White, Tom (2011). Version
Control with Git: Powerful Tools
and Techniques for
Collaborative Software
Developement. Sebastopol, CA:
O’Reilly.
 Wikipedia – Git (software)
 What is Free Software?
From the GNU Project
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