CIT-WEB-301

Software Versioning

Department of
Computer Science and Information Systems
(CSIS)
 Outline
● Version Control Systems
● Types of version control systems
● Git
● Git installation
● Creating repositories
● Working with local repositories
● GitHub
● GitHub workflows
● Working with remote repositories
 Unit outcomes
By the end of this lesson, you should be able to:
─ Explain the term version control system (VCS)
─ Discuss the different types of VCS
─ Install and configure git
─ Create repositories with git
─ Manage local repositories
─ Work with GitHub
─ Manage remote repositories on GitHub
 What is a Version Control System?
● A system capable of recording the changes
made to a file or a set of files over time and
enables the restoration of old versions.
● Why is it important?
─ Track file changes over time
─ Enable collaboration
─ Enables branching
─ Backup and restoration
─ Provide history of changes
 Cont..
● In a manual system, you
must keep changes of
the files as different
copies.
● To go to a previous one,
you must restore it,
potentially losing some
good updates.
 Cont..
● In a VCS you mark the
changes made as a
stage with a marker.
● You can easily go to the
previous stage using the
marker.
● No need to be manually
saving the whole
project.
 Types of Version Control Systems
● Local Version Control Systems
─ All changes are stored in a local database.
─ It is limited to single-user scenarios.
● Centralized Version Control Systems
─ Uses a single server to store all the versioned files
─ Clients check out files from this central place.
● Distributed Version Control Systems
─ Every contributor has a local copy of the entire
project history.
 Git
● Git is a free and open-source distributed
version control system designed to track
changes in computer code and other
projects.
─ Initially developed to manage Linux kernel
project
─ Every developer can have a copy of the project
─ It enables collaboration
 Using Git
● Download Git from
https://git-scm.com/downloads
and install it.
● There are two versions;
command line and GUI
● In this tutorial, the command line
version will be used.
● Open the application, you will be
presented with a command
prompt.
 Git
● First things first, configure Git.
● Chances are high that you are going to work
on a remote repository.
● There are three types of configurations.
─ System level- All users on the system and all
their repositories.
─ Global level- Currently logged-in user and all
their repositories.
─ Local level: A specific repository.
 Configure git
● The following are
some of the
important
configurations.
 Initialising a git Repository
● When you have created a
project, you'll need to tell
git that is a git repository.
● It creates a hidden folder
called git
● You can also get a copy
of a repository from a
server
 The README.md file
● Is a text file typically included
in software projects,
websites, or repositories.
● It serves as a starting point
for anyone encountering the
project.
● Provides essential information
and instructions.
 The README.md file
● The file can contain the following
information
─ Project Overview: project description
─ Installation Instructions: how users
can install the software
─ Usage Guide: how users can run the
software
─ License Information: How others
can use, modify, and distribute the
code.
 Mark down elements
● Headings: supports
several levels of headings
● Paragraph: Each line is a
paragraph
● Bold & italicize text
formatting.
● List: ordered and
unordered lists.
etc
 Recording Changes to the Repo
● Git is aware of file
changes.
● Use the status command
to see untracked files.
● Add the files to the
staging area to commit
the changes
● Save the changes using
the commit command.
 Ignoring files
● There could be some files and
directories that you don’t want
git to track.
● The .gitignore file is used to
tell Git which files or
directories to ignore in a
project.
● Create the file and include the
list of files & dirs to ignore
 GitHub
● GitHub is a web-based
platform that uses Git for
version control.
● Other features are specific to
GitHub and not Git
─ Pull request
─ Repository forking
─ Issue tracking
 GitHub- workflows
● Centralized workflow
─ There is a centralized repo
─ Team members clone the repo and work on it
─ Team members push & updates to the repo
● Integration manager
─ One member has push access to the repo
─ Contributors folk and clone the repo.
─ Contributors make pull request to the manager
─ The manager pulls and pushes the updates (if
happy)
 Using GitHub
● Create an account, its free.
● Create a repository
─ Specify the name
─ Description
─ Visibility
─ Readme file (optional)
─ .gitignore file (optional)
─ License (optional)
 Remote – Local connection
● Create a local repository
● Use “git init”
● Use git remote add
origin command to
connect the local repo to
the remote repo.
● Set personal access
tokens (GitHub does not
accept passwords)
 Git log
● Allows you to view the
history of commits in a
repository.
● Provides a detailed
information such as
commit IDs, author names,
commit messages, and
dates.
 Git restore
● The command can be
used to restore
files/directories from
previous commits.
● It can also be used to
restore remove files from
the staging area.
 Git checkout
● This command switches
your working directory to
the state at a particular
commit.
● It results into “HEAD
detached state”- you're not
on any branch.
● Create a branch from
there or go to any branch.
 Git branch
● The git branch
command is used to
manage branches in a
Git repository.
● Branches allow you to
work on different
versions of your project
simultaneously.
 Git branch
● The git branch
command is used to
manage branches in a
Git repository.
● Branches allow you to
work on different
versions of your project
simultaneously.
 Git stash
● The git stash command is
used to temporarily save
changes that you've made
in your working directory.
● It enables going into
another branch, comeback
later and restore the
untracked & uncommitted
changes.
 Git merge
● The git merge command is used
to integrate changes from one
branch into another.
● The merge process:
─ Ensure your working directory is
clean
─ Switch to the target branch
─ Merge the source branch into the
target branch
 Git merge- Strategies
● Fast-Forward
Merge- moves the
pointer of the
target branch
forward to the
latest commit in
the source
branch.
 Git merge- Strategies
● Three-Way
Merge-This involves
creating a new merge
commit that has two
parent commits: one
from the target branch
and one from the
source branch.
 Handling Merge Conflicts
● Conflicts occur when changes in the
source branch and the target branch
overlap.
● When this happens, Git will stop and
allow you to resolve the conflicts
manually.
─ Make different changes to the same line
─ One person edits a file and another
person deletes
 Handling Merge Conflicts
● Conflicts occur when changes in the
source branch and the target branch
overlap.
● When this happens, Git will stop and
allow you to resolve the conflicts
manually.
─ Make different changes to the same line
─ One person edits a file and another
person deletes
 Handling Merge Conflicts
● The process is as follows:
─ Start the merge
─ Git identifies conflicts
─ Resolve conflicts
─ Add the resolved files
─ Commit the merge
o Fix options
─ Accept current change
─ Accept incoming change
─ Accept both
─ etc.
 Undoing commits
● You can undo a merge
after the merge was done
and committed or before
commit.
● If its before commit use
the –abort argument
● If its after the merge use
git reset option.