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Git Git and GitHub

Git is the version-control system. GitHub is one hosting and collaboration service built around Git repositories, accounts and additional workflows.

How it works

The exercise inspects a real local origin and stores a fictional HTTPS host address only in a reading file. It does not create a GitHub repository, sign in, push online or test permissions. In a real hosted setup, first choose the owner, visibility and license policy, then inspect the destination before publishing history. A private repository still needs appropriate access controls and secret handling.

Run the disposable lab

Use Windows PowerShell 5.1 or later and Git 2.28 or later. The reviewed CLI is Git for Windows 2.53.0.windows.2. These are PowerShell examples, not Git Bash commands. Save the download as github.ps1 in a separate empty learning folder and run it in a separate process: powershell -NoProfile -ExecutionPolicy Bypass -File .\github.ps1. The execution-policy option applies to that process, not your machine policy.

The script creates bhylu-git-github and refuses an existing folder. It supplies two fictional seed files and repository-local settings, then runs the lesson commands. The literal separator is quoted as '--' so PowerShell passes it through the guard. A guard function named git calls the real CLI and stops on unexpected failures; Expect-GitFailure checks deliberately refused operations. Child-process configuration isolates your personal Git settings. File transports are allowed only for owned local remotes; internet transports are disabled in this lab. No hosting account, Apache or MySQL service is required. There is no Git playground. Leave the generated folder for inspection; choose another empty parent to run again.

Test boundary: Hosted account creation and browser editing are explained, not performed.

Download the complete github.ps1 lab

Example

github.ps1

# Bhylu Git lab: Git and GitHub
# Run in a separate PowerShell process, in an empty learning folder.
# Existing lab folders are refused; nothing is pushed to an internet host.
$ErrorActionPreference = 'Stop'
$script:GitExe = (Get-Command git -CommandType Application | Select-Object -First 1).Source
$script:LabRoot = Join-Path (Get-Location) 'bhylu-git-github'
if (Test-Path -LiteralPath $script:LabRoot) { throw 'Lab folder already exists. Choose another empty parent folder.' }
New-Item -ItemType Directory -Path $script:LabRoot | Out-Null
$env:GIT_CONFIG_NOSYSTEM = '1'
$env:GIT_CONFIG_GLOBAL = Join-Path $script:LabRoot 'empty-global-config'
[IO.File]::WriteAllText($env:GIT_CONFIG_GLOBAL, '')
$env:GIT_TERMINAL_PROMPT = '0'
$env:GIT_EDITOR = 'true'
$env:GIT_SEQUENCE_EDITOR = 'true'
$env:GIT_AUTHOR_DATE = '2026-01-10T10:00:00+00:00'
$env:GIT_COMMITTER_DATE = $env:GIT_AUTHOR_DATE
function git {
    & $script:GitExe -c protocol.allow=never -c protocol.file.allow=always @args
    if ($LASTEXITCODE -ne 0) { throw "Git exited with code $LASTEXITCODE" }
}
function Expect-GitFailure {
    & $script:GitExe -c protocol.allow=never -c protocol.file.allow=always @args
    if ($LASTEXITCODE -eq 0) { throw 'Expected Git to refuse this operation' }
}
function Assert-Equal($Actual, $Expected) {
    if ((($Actual | Out-String).Trim()) -cne (($Expected | Out-String).Trim())) { throw "Expected [$Expected], got [$Actual]" }
}
function Write-LabFile([string]$Name, [string]$Text) {
    $target = [IO.Path]::GetFullPath((Join-Path (Get-Location) $Name))
    if (!$target.StartsWith($script:LabRoot + [IO.Path]::DirectorySeparatorChar, [StringComparison]::OrdinalIgnoreCase)) { throw 'Path outside lab' }
    [IO.Directory]::CreateDirectory([IO.Path]::GetDirectoryName($target)) | Out-Null
    [IO.File]::WriteAllText($target, ($Text.Replace('\n', "`n") + "`n"), (New-Object Text.UTF8Encoding($false)))
}
function New-LabRepo([string]$Name) {
    New-Item -ItemType Directory -Path $Name | Out-Null
    Push-Location $Name
    try {
        git init --initial-branch=main
        git config --local user.name 'Repair Lab'
        git config --local user.email 'repair@example.invalid'
        git config --local core.autocrlf false
        git config --local commit.gpgSign false
        git config --local tag.gpgSign false
        git config --local core.hooksPath (Join-Path $script:LabRoot 'empty-hooks')
        Write-LabFile 'notes.md' 'Inspect hinge'
        Write-LabFile 'tasks.txt' 'desk=open'
        git add '--' notes.md tasks.txt
        git commit -m 'Record initial repair plan'
    } finally { Pop-Location }
}
Push-Location $script:LabRoot
try {
    New-LabRepo 'desk'
    Set-Location desk
    git init --bare --initial-branch=main ../shared.git
    git remote add origin ../shared.git
    git push -u origin main
    Write-LabFile '../host-reading.txt' 'https://github.com/OWNER/REPOSITORY.git'
    Assert-Equal (git remote get-url origin) @('../shared.git')
    Assert-Equal (Get-Content ../host-reading.txt) @('https://github.com/OWNER/REPOSITORY.git')
    Write-Output 'Verified: github'
} finally { Pop-Location }
Focus on the lesson commands

This excerpt omits the seed repository and guard helpers. Use the complete download to run it.

Lesson excerpt

git init --bare --initial-branch=main ../shared.git
git remote add origin ../shared.git
git push -u origin main
Write-LabFile '../host-reading.txt' 'https://github.com/OWNER/REPOSITORY.git'
Assert-Equal (git remote get-url origin) @('../shared.git')
Assert-Equal (Get-Content ../host-reading.txt) @('https://github.com/OWNER/REPOSITORY.git')

Expected result

origin remains the local exchange repository. The GitHub address is a placeholder reading example, not an active remote.

The complete script ends with Verified: github only after its checks pass. Object IDs, temporary paths and progress output can differ.

Git commits, branches and tags are portable concepts. Issues, discussions, pull requests, releases and access rules belong to the hosting layer. If you edit a file through a hosted web editor, that produces a remote commit which your local clone must fetch and integrate.

Official reference

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