How to sparsely checkout only one single file from a git repository?

Question

How do I checkout just one file from a git repo?

Answer 1

If you have edited a local version of a file and wish to revert to the original version maintained on the central server, this can be easily achieved using Git Extensions.

• Initially the file will be marked for commit, since it has been modified
• Select (double click) the file in the file tree menu
• The revision tree for the single file is listed.
• Select the top/HEAD of the tree and right click save as
• Save the file to overwrite the modified local version of the file
• The file now has the correct version and will no longer be marked for commit!

Easy!

Answer 2

It sounds like you're trying to carry over an idea from centralized version control, which git by nature is not - it's distributed. If you want to work with a git repository, you clone it. You then have all of the contents of the work tree, and all of the history (well, at least everything leading up to the tip of the current branch), not just a single file or a snapshot from a single commit.

 git clone /path/to/repo
 git clone git://url/of/repo
 git clone http://url/of/repo

Answer 3

You can do it by

git archive --format=tar --remote=origin HEAD | tar xf -
git archive --format=tar --remote=origin HEAD <file> | tar xf -

Answer 4

If you only need to download the file, no need to check out with Git.

GitHub Mate is much easier to do so, it's a Chrome extension, enables you click the file icon to download it. also open source

Answer 5

First clone the repo with the -n option, which suppresses the default checkout of all files, and the --depth 1 option, which means it only gets the most recent revision of each file

git clone -n git://path/to/the_repo.git --depth 1

Then check out just the file you want like so:

cd the_repo
git checkout HEAD name_of_file

Answer 6

git clone --filter from Git 2.19

This option will actually skip fetching most unneeded objects from the server:

git clone --depth 1 --no-checkout --filter=blob:none \
  "file://$(pwd)/server_repo" local_repo
cd local_repo
git checkout master -- mydir/myfile

The server should be configured with:

git config --local uploadpack.allowfilter 1
git config --local uploadpack.allowanysha1inwant 1

There is no server support as of v2.19.0, but it can already be locally tested.

TODO: --filter=blob:none skips all blobs, but still fetches all tree objects. But on a normal repo, this should be tiny compared to the files themselves, so this is already good enough. Asked at: https://www.spinics.net/lists/git/msg342006.html Devs replied a --filter=tree:0 is in the works to do that.

Remember that --depth 1 already implies --single-branch, see also: How do I clone a single branch in Git?

file://$(path) is required to overcome git clone protocol shenanigans: How to shallow clone a local git repository with a relative path?

The format of --filter is documented on man git-rev-list.

An extension was made to the Git remote protocol to support this feature.

Docs on Git tree:

• https://github.com/git/git/blob/v2.19.0/Documentation/technical/partial-clone.txt
• https://github.com/git/git/blob/v2.19.0/Documentation/rev-list-options.txt#L720
• https://github.com/git/git/blob/v2.19.0/t/t5616-partial-clone.sh

Test it out

#!/usr/bin/env bash
set -eu

list-objects() (
  git rev-list --all --objects
  echo "master commit SHA: $(git log -1 --format="%H")"
  echo "mybranch commit SHA: $(git log -1 --format="%H")"
  git ls-tree master
  git ls-tree mybranch | grep mybranch
  git ls-tree master~ | grep root
)

# Reproducibility.
export GIT_COMMITTER_NAME='a'
export GIT_COMMITTER_EMAIL='a'
export GIT_AUTHOR_NAME='a'
export GIT_AUTHOR_EMAIL='a'
export GIT_COMMITTER_DATE='2000-01-01T00:00:00+0000'
export GIT_AUTHOR_DATE='2000-01-01T00:00:00+0000'

rm -rf server_repo local_repo
mkdir server_repo
cd server_repo

# Create repo.
git init --quiet
git config --local uploadpack.allowfilter 1
git config --local uploadpack.allowanysha1inwant 1

# First commit.
# Directories present in all branches.
mkdir d1 d2
printf 'd1/a' > ./d1/a
printf 'd1/b' > ./d1/b
printf 'd2/a' > ./d2/a
printf 'd2/b' > ./d2/b
# Present only in root.
mkdir 'root'
printf 'root' > ./root/root
git add .
git commit -m 'root' --quiet

# Second commit only on master.
git rm --quiet -r ./root
mkdir 'master'
printf 'master' > ./master/master
git add .
git commit -m 'master commit' --quiet

# Second commit only on mybranch.
git checkout -b mybranch --quiet master~
git rm --quiet -r ./root
mkdir 'mybranch'
printf 'mybranch' > ./mybranch/mybranch
git add .
git commit -m 'mybranch commit' --quiet

echo "# List and identify all objects"
list-objects
echo

# Restore master.
git checkout --quiet master
cd ..

# Clone. Don't checkout for now, only .git/ dir.
git clone --depth 1 --quiet --no-checkout --filter=blob:none "file://$(pwd)/server_repo" local_repo
cd local_repo

# List missing objects from master.
echo "# Missing objects after --no-checkout"
git rev-list --all --quiet --objects --missing=print
echo

echo "# Git checkout fails without internet"
mv ../server_repo ../server_repo.off
! git checkout master
echo

echo "# Git checkout fetches the missing file from internet"
mv ../server_repo.off ../server_repo
git checkout master -- d1/a
echo

echo "# Missing objects after checking out d1/a"
git rev-list --all --quiet --objects --missing=print

GitHub upstream.

Output in Git v2.19.0:

# List and identify all objects
c6fcdfaf2b1462f809aecdad83a186eeec00f9c1
fc5e97944480982cfc180a6d6634699921ee63ec
7251a83be9a03161acde7b71a8fda9be19f47128
62d67bce3c672fe2b9065f372726a11e57bade7e
b64bf435a3e54c5208a1b70b7bcb0fc627463a75 d1
308150e8fffffde043f3dbbb8573abb6af1df96e63 d1/a
f70a17f51b7b30fec48a32e4f19ac15e261fd1a4 d1/b
84de03c312dc741d0f2a66df7b2f168d823e122a d2
0975df9b39e23c15f63db194df7f45c76528bccb d2/a
41484c13520fcbb6e7243a26fdb1fc9405c08520 d2/b
7d5230379e4652f1b1da7ed1e78e0b8253e03ba3 master
8b25206ff90e9432f6f1a8600f87a7bd695a24af master/master
ef29f15c9a7c5417944cc09711b6a9ee51b01d89
19f7a4ca4a038aff89d803f017f76d2b66063043 mybranch
1b671b190e293aa091239b8b5e8c149411d00523 mybranch/mybranch
c3760bb1a0ece87cdbaf9a563c77a45e30a4e30e
a0234da53ec608b54813b4271fbf00ba5318b99f root
93ca1422a8da0a9effc465eccbcb17e23015542d root/root
master commit SHA: fc5e97944480982cfc180a6d6634699921ee63ec
mybranch commit SHA: fc5e97944480982cfc180a6d6634699921ee63ec
040000 tree b64bf435a3e54c5208a1b70b7bcb0fc627463a75    d1
040000 tree 84de03c312dc741d0f2a66df7b2f168d823e122a    d2
040000 tree 7d5230379e4652f1b1da7ed1e78e0b8253e03ba3    master
040000 tree 19f7a4ca4a038aff89d803f017f76d2b66063043    mybranch
040000 tree a0234da53ec608b54813b4271fbf00ba5318b99f    root

# Missing objects after --no-checkout
?f70a17f51b7b30fec48a32e4f19ac15e261fd1a4
?8b25206ff90e9432f6f1a8600f87a7bd695a24af
?41484c13520fcbb6e7243a26fdb1fc9405c08520
?0975df9b39e23c15f63db194df7f45c76528bccb
?308150e8fffffde043f3dbbb8573abb6af1df96e63

# Git checkout fails without internet
fatal: '/home/ciro/bak/git/test-git-web-interface/other-test-repos/partial-clone.tmp/server_repo' does not appear to be a git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

# Git checkout fetches the missing directory from internet
remote: Enumerating objects: 1, done.
remote: Counting objects: 100% (1/1), done.
remote: Total 1 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (1/1), 45 bytes | 45.00 KiB/s, done.
remote: Enumerating objects: 1, done.
remote: Counting objects: 100% (1/1), done.
remote: Total 1 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (1/1), 45 bytes | 45.00 KiB/s, done.

# Missing objects after checking out d1
?f70a17f51b7b30fec48a32e4f19ac15e261fd1a4
?8b25206ff90e9432f6f1a8600f87a7bd695a24af
?41484c13520fcbb6e7243a26fdb1fc9405c08520
?0975df9b39e23c15f63db194df7f45c76528bccb

Conclusions: all blobs except d1/a are missing. E.g. f70a17f51b7b30fec48a32e4f19ac15e261fd1a4, which is d1/b, is not there after checking out d1/.

Note that root/root and mybranch/mybranch are also missing, but --depth 1 hides that from the list of missing files. If you remove --depth 1, then they show on the list of missing files.