Git: Difference between revisions

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Git is a popular version control system made by Linus Torvalds.

==~~Usage~~==

==Installation==

===Basic Usage===

===Windows===

Download [https://git-scm.com/downloads Git for Windows] or use [https://community.chocolatey.org/packages/git chocolatey].

<pre>

choco install git --params "/WindowsTerminalProfile"

</pre>

===Linux===

[https://git-scm.com/download/linux git-scm install]

# PPA for the latest stable version.

sudo add-apt-repository ppa:git-core/ppa

sudo apt update

sudo apt install git git-lfs

</syntaxhighlight>

==Basic Usage==

# Clone or download a repository

git clone <url>

git clone <url> [<foldername>]

# cd into the cloned folder

cd <foldername>

# Note that some repos have submodules which will also need to be cloned

git submodule update --init --recursive

# Stage your changes

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</syntaxhighlight>

===Branches===

==Branches==

Branches allow you to work on the repository without creating new forks and using more disk space.

You can use them to create and test changes from a static copy of the code repo.

You can also discard a branch if you decide the feature is no longer needed.

Once the feature has been fully developed, you should rebase the branch onto the head of the main branch.

Then you can merge the branch to add the feature to main/master.

# Make a branch

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# Push

git push --set-upstream origin my_feature

# Checkout a branch

git checkout my_branch

# Checkout a single file from another branch

git checkout my_branch -- other_file.txt

</syntaxhighlight>

==Patches==

Patches are a way to represent and share changes without actually making commits or new branches.

# For unstaged changes

git diff > changes.patch

# For staged changes

git diff --cached > changes.patch

# You can also add --binary to include binary files

# Apply the patch

git apply changes.patch

</syntaxhighlight>

See [https://stackoverflow.com/questions/5159185/create-a-git-patch-from-the-uncommitted-changes-in-the-current-working-directory create git patch]

===Pull Requests===

==Pull Requests==

See [https://stackoverflow.com/questions/20289599/are-pull-requests-part-of-git-or-a-feature-of-tools-like-github-gerrit-and-atl Are pull requests are part of Git?]

===Migrating Repositories===

Pull requests are a way to submit changes to repositories you do not manage.

First, you fork the repository to create a working-copy for yourself to develop on.

Once your changes are finished, you create a pull request asking the original repo to incorporate your changes.

It's easiest to just use the web interfaces of GitHub or GitLab for this.

To do this manually, see [https://git-scm.com/book/en/v2/Distributed-Git-Contributing-to-a-Project Git Book: Contributing to a project].

==Migrating Repositories==

How to migrate repositories to another Git server

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</syntaxhighlight>

===Changing Remote URL===

==Changing Remote URL==

[https://help.github.com/en/articles/changing-a-remotes-url Reference]

You will need to change the remote url if it is changed on the server. E.g. if you change the project name.

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</syntaxhighlight>

===gitignore===

==Special Files==

.gitignore is used to ignore certain files to make sure they do not get accidentally pushed to the remote git repo.

===<code>.gitignore</code>===

<code>.gitignore</code> is used to ignore certain files to make sure they do not get accidentally pushed to the remote git repo.

You can find a collection of .gitignore files on [https://github.com/github/gitignore Github's gitignore repo].

Or you can create a custom .gitignore file at [https://www.gitignore.io gitignore.io].

===gitattributes===

===<code>.gitattributes</code>===

.gitattributes are used to give attributes to paths.

<code>.gitattributes</code> are used to give attributes to paths.

They can be used to assign programming languages to filenames.

They are also used to identify which files should be stored in the lfs.

Here is an example to store video and images in the lfs.

[https://gitlab.davidl.me/-/snippets/1/raw/master/lfs.gitattributes Here] is an example to store video and images in the lfs.

~~<pre>~~

~~## Video~~

*.mp4 filter=lfs diff=lfs merge=lfs -text

*.mov filter=lfs diff=lfs merge=lfs -text

*.flv filter=lfs diff=lfs merge=lfs -text

~~## Pictures~~

==Clean==

*.png filter=~~lfs diff~~=~~lfs merge~~=~~lfs -text~~

[https://www.atlassian.com/git/tutorials/undoing-changes/git-clean Atlassian Reference]

*.~~jpg filter=lfs diff=lfs merge=lfs~~ -~~text~~

Use <code>git clean</code> to delete untracked files.

*.~~jpeg filter=lfs diff=lfs merge=lfs~~ -~~text~~

Add <code>-x</code> to also delete gitignore'd files.

#~~# Binary~~ files

# Force delete any untracked files and directories

*.bin filter=lfs diff=lfs merge=lfs -text

git clean -fd

*.7z filter=lfs diff=lfs merge=lfs -~~text~~

</syntaxhighlight>

</~~pre~~>

==Git Large File Storage (LFS)==

[https://github.com/git-lfs/git-lfs/wiki/Tutorial Reference]

* Note that Github charges for LFS so it's best to keep binary files outside of GitHub.

==Sparse checkout==

If you're interacting with a monorepo like [https://github.com/google-research/google-research google-research/google-research], you may be interested in git sparse checkout.

See [https://git-scm.com/docs/git-sparse-checkout Git - git-sparse-checkout Documentation] and [https://github.blog/2020-01-17-bring-your-monorepo-down-to-size-with-sparse-checkout/ Bring your monorepo down to size with sparse-checkout | The GitHub Blog].

This is a relatively new feature so be sure to use an updated version of git.

git clone --no-checkout $url

cd $project

git sparse-checkout init

git sparse-checkout add $folder

</syntaxhighlight>

@@ Line 1: / Line 1: @@
 Git is a popular version control system made by Linus Torvalds.
-==Usage==
+==Installation==
-===Basic Usage===
+===Windows===
+Download [https://git-scm.com/downloads Git for Windows] or use [https://community.chocolatey.org/packages/git chocolatey].
+<pre>
+choco install git --params "/WindowsTerminalProfile"
+</pre>
+===Linux===
+[https://git-scm.com/download/linux git-scm install]
+<syntaxhighlight lang="bash">
+# PPA for the latest stable version.
+sudo add-apt-repository ppa:git-core/ppa
+sudo apt update
+sudo apt install git git-lfs
+</syntaxhighlight>
+==Basic Usage==
 <syntaxhighlight lang="bash">
 # Clone or download a repository
-git clone <url>
+git clone <url> [<foldername>]
+# cd into the cloned folder
+cd <foldername>
+# Note that some repos have submodules which will also need to be cloned
+git submodule update --init --recursive
 # Stage your changes
@@ Line 23: / Line 42: @@
 </syntaxhighlight>
-===Branches===
+==Branches==
+Branches allow you to work on the repository without creating new forks and using more disk space.
+You can use them to create and test changes from a static copy of the code repo.
+You can also discard a branch if you decide the feature is no longer needed.
+Once the feature has been fully developed, you should rebase the branch onto the head of the main branch.
+Then you can merge the branch to add the feature to main/master.
 <syntaxhighlight lang="bash">
 # Make a branch
@@ Line 34: / Line 59: @@
 # Push
 git push --set-upstream origin my_feature
+# Checkout a branch
+git checkout my_branch
+# Checkout a single file from another branch
+git checkout my_branch -- other_file.txt
+</syntaxhighlight>
+==Patches==
+Patches are a way to represent and share changes without actually making commits or new branches.
+<syntaxhighlight lang="bash">
+# For unstaged changes
+git diff > changes.patch
+# For staged changes
+git diff --cached > changes.patch
+# You can also add --binary to include binary files
+# Apply the patch
+git apply changes.patch
 </syntaxhighlight>
+See [https://stackoverflow.com/questions/5159185/create-a-git-patch-from-the-uncommitted-changes-in-the-current-working-directory create git patch]
-===Pull Requests===
+==Pull Requests==
+See [https://stackoverflow.com/questions/20289599/are-pull-requests-part-of-git-or-a-feature-of-tools-like-github-gerrit-and-atl Are pull requests are part of Git?]
-===Migrating Repositories===
+Pull requests are a way to submit changes to repositories you do not manage.
+First, you fork the repository to create a working-copy for yourself to develop on.
+Once your changes are finished, you create a pull request asking the original repo to incorporate your changes.
+It's easiest to just use the web interfaces of GitHub or GitLab for this.
+To do this manually, see [https://git-scm.com/book/en/v2/Distributed-Git-Contributing-to-a-Project Git Book: Contributing to a project].
+==Migrating Repositories==
 How to migrate repositories to another Git server
 <syntaxhighlight lang="bash">
@@ Line 51: / Line 104: @@
 </syntaxhighlight>
-===Changing Remote URL===
+==Changing Remote URL==
 [https://help.github.com/en/articles/changing-a-remotes-url Reference]<br>
 You will need to change the remote url if it is changed on the server. E.g. if you change the project name.<br>
@@ Line 58: / Line 111: @@
 </syntaxhighlight>
-===gitignore===
+==Special Files==
-.gitignore is used to ignore certain files to make sure they do not get accidentally pushed to the remote git repo.<br>
+===<code>.gitignore</code>===
+<code>.gitignore</code> is used to ignore certain files to make sure they do not get accidentally pushed to the remote git repo.<br>
 You can find a collection of .gitignore files on [https://github.com/github/gitignore Github's gitignore repo].<br>
 Or you can create a custom .gitignore file at [https://www.gitignore.io gitignore.io].
-===gitattributes===
+===<code>.gitattributes</code>===
-.gitattributes are used to give attributes to paths.<br>
+<code>.gitattributes</code> are used to give attributes to paths.<br>
 They can be used to assign programming languages to filenames.<br>
 They are also used to identify which files should be stored in the lfs.<br>
-Here is an example to store video and images in the lfs.<br>
+[https://gitlab.davidl.me/-/snippets/1/raw/master/lfs.gitattributes Here] is an example to store video and images in the lfs.<br>
-<pre>
-## Video
-*.mp4 filter=lfs diff=lfs merge=lfs -text
-*.mov filter=lfs diff=lfs merge=lfs -text
-*.flv filter=lfs diff=lfs merge=lfs -text
-## Pictures
+==Clean==
-*.png filter=lfs diff=lfs merge=lfs -text
+[https://www.atlassian.com/git/tutorials/undoing-changes/git-clean Atlassian Reference]<br>
-*.jpg filter=lfs diff=lfs merge=lfs -text
+Use <code>git clean</code> to delete untracked files.<br>
-*.jpeg filter=lfs diff=lfs merge=lfs -text
+Add <code>-x</code> to also delete gitignore'd files.
+<syntaxhighlight lang="bash">
-## Binary files
+# Force delete any untracked files and directories
-*.bin filter=lfs diff=lfs merge=lfs -text
+git clean -fd
-*.7z filter=lfs diff=lfs merge=lfs -text
+</syntaxhighlight>
-</pre>
 ==Git Large File Storage (LFS)==
 [https://github.com/git-lfs/git-lfs/wiki/Tutorial Reference]
+* Note that Github charges for LFS so it's best to keep binary files outside of GitHub.
+==Sparse checkout==
+If you're interacting with a monorepo like [https://github.com/google-research/google-research google-research/google-research], you may be interested in git sparse checkout.<br>
+See [https://git-scm.com/docs/git-sparse-checkout Git - git-sparse-checkout Documentation] and [https://github.blog/2020-01-17-bring-your-monorepo-down-to-size-with-sparse-checkout/ Bring your monorepo down to size with sparse-checkout | The GitHub Blog].<br>
+This is a relatively new feature so be sure to use an updated version of git.
+<syntaxhighlight lang="bash">
+git clone --no-checkout $url
+cd $project
+git sparse-checkout init
+git sparse-checkout add $folder
+</syntaxhighlight>