Git Fetch
git fetch downloads reachable objects and updates selected remote-tracking references. It does not automatically integrate those commits into your current branch.
How it works
A local writer clone advances the shared main branch. The original desk fetches, then compares its main with origin/main. Its working note remains the original value while the remote-tracking snapshot has the new text. This separates learning about remote work from deciding how to integrate it.
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 fetch.ps1 in a separate empty learning folder and run it in a separate process: powershell -NoProfile -ExecutionPolicy Bypass -File .\fetch.ps1. The execution-policy option applies to that process, not your machine policy.
The script creates bhylu-git-fetch 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.
Example
# Bhylu Git lab: Fetch
# 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-fetch'
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
git clone ../shared.git ../writer
git -C ../writer config user.name 'Repair Lab'
git -C ../writer config user.email 'repair@example.invalid'
Push-Location ../writer
try {
Write-LabFile 'notes.md' 'Remote inspection update'
git add '--' 'notes.md'
git commit -m 'Share inspection update'
git push origin main
} finally { Pop-Location }
git fetch origin
Assert-Equal (Get-Content notes.md) @('Inspect hinge')
Assert-Equal (git show origin/main:notes.md) @('Remote inspection update')
Assert-Equal (git rev-list --count main..origin/main) @('1')
Write-Output 'Verified: fetch'
} finally { Pop-Location }
Focus on the lesson commands
This excerpt omits the seed repository and guard helpers. Use the complete download to run it.
git init --bare --initial-branch=main ../shared.git
git remote add origin ../shared.git
git push -u origin main
git clone ../shared.git ../writer
git -C ../writer config user.name 'Repair Lab'
git -C ../writer config user.email 'repair@example.invalid'
Push-Location ../writer
try {
Write-LabFile 'notes.md' 'Remote inspection update'
git add '--' 'notes.md'
git commit -m 'Share inspection update'
git push origin main
} finally { Pop-Location }
git fetch origin
Assert-Equal (Get-Content notes.md) @('Inspect hinge')
Assert-Equal (git show origin/main:notes.md) @('Remote inspection update')
Assert-Equal (git rev-list --count main..origin/main) @('1')
Expected result
The working note is unchanged; origin/main has one additional commit with the remote update.
The complete script ends with Verified: fetch only after its checks pass. Object IDs, temporary paths and progress output can differ.
Remote-tracking references are local records of fetched state and can become stale immediately after a fetch. They are not live views of another computer. Inspect the graph or diff before merge or rebase.