Despite having used git for years, I find git lfs (git Large File Storage) to be pretty confusing to use, even at a very basic level. Can someone explain the difference between these 3 commands?:
git lfs fetchgit lfs fetch --allgit lfs pullRelated:
Update 5 May 2023: to anyone thinking of using git lfs, don't! See my explanation in my question here, in this section: Update: don't use git lfs. I now recommend against using git lfs, and in my answer here.
For personal, free GitHub accounts, it is way too limiting, and for paid, corporate accounts, it makes git checkout go from taking a few seconds to up to 3+ hours, especially for remote workers, which is a total waste of their time. I dealt with that for three years and it was horrible. I wrote a script to do a git lfs fetch once per night to mitigate this, but my employer refused to buy me a bigger SSD to give me enough space to do git lfs fetch --all once per night, so I still ran into the multi-hour-checkout problem frequently. It's also impossible to undo the integration of git lfs into your repo unless you delete your whole GitHub repo and recreate it from scratch.
In both cases: corporate and free, with over 3 years of daily experience using it, I have found git lfs to be a massive time-waster.
If you are forced to use git lfs by your employer, however, here's what you need to know:
Now on to the answer:
After a bunch of study and figuring out where the help pages are, here is what I have concluded:
git lfs as a basic userThis covers the question: "What is the difference between git lfs fetch, git lfs fetch --all, git lfs pull, and git lfs checkout?"
# Fetch git lfs files for just the currently-checked-out branch or commit (Ex: 20
# GB of data). This downloads the files into your `.git/lfs` dir but does NOT
# update them in your working file system for the branch or commit you have
# currently checked-out.
git lfs fetch
# Fetch git lfs files for ALL remote branches (Ex: 1000 GB of data), downloading
# all files into your `.git/lfs` directory.
git lfs fetch --all
# Fetch git lfs files for just these 3 branches (Ex: 60 GB of data)
# See `man git-lfs-fetch` for details. The example they give is:
# `git lfs fetch origin main mybranch e445b45c1c9c6282614f201b62778e4c0688b5c8`
git lfs fetch origin main mybranch1 mybranch2
# Check out, or "activate" the git lfs files for your currently-checked-out
# branch or commit, by updating all file placeholders or pointers in your
# active filesystem for the current branch with the actual files these git lfs
# placeholders point to.
git lfs checkout
# Fetch and check out in one step. This one command is the equivalent of these 2
# commands:
# git lfs fetch
# git lfs checkout
git lfs pull
#
# Note that `git lfs pull` is similar to how `git pull` is the equivalent
# of these 2 commands:
# git fetch
# git merge
So, a general, recommended workflow to check out your git files and your git lfs files might look like this:
git checkout main # check out your `main` branch
git pull # pull latest git files from the remote, for this branch
git lfs pull # pull latest git lfs files from the remote, for this branch
# OR (exact same thing)
git checkout main # check out your `main` branch
# (The next 2 commands replace `git pull`)
git fetch # fetch the latest files from the remote for branch `main`
# into your locally-stored hidden remote-tracking branch
# named `origin/main`, for example
git merge # merge the latest content (which you just fetched
# into your local hidden branch `origin/main`)
# into non-hidden branch `main`
# (The next 2 commands replace `git lfs pull`)
git lfs fetch # fetch latest git lfs files from the remote, for this
# branch
git lfs checkout # check out all git lfs files for this branch, replacing
# git lfs file placeholders with the actual files
git lfs fetchSee man git-lfs-fetch, and git lfs fetch --help.
From git lfs fetch --help (emphasis added):
Download Git LFS objects at the given refs from the specified remote. See "Default remote" and "Default refs" for what happens if you don't specify.
This does not update the working copy.
So, this is just like doing git fetch (where it fetches remote contents to your locally-stored, remote-tracking hidden branches), except it is for git lfs-controlled files.
It fetches the git lfs file content to your .git/lfs directory I believe, but does NOT update your active file system (the currently checked-out branch) with those files.
From farther down in the help menu (emphasis added):
Default remote
Without arguments, fetch downloads from the default remote. The default remote is the same as for
git fetch, i.e. based on the remote branch you're tracking first, or origin otherwise.Default refs
If no refs are given as arguments, the currently checked out ref is used. In addition, if enabled, recently changed refs and commits are also included. See "Recent changes" for details.
Note that the "currently checked-out ref" refers to your currently-checked out branch or commit.
git lfs fetch --allWhereas git lfs fetch fetches only the content for your currently-checked-out branch or commit, by default, git lfs fetch --all checks out ALL content for ALL remote branches. On a gigantic corporate mono-repo, that means that git lfs fetch might fetch 20 GB of data, whereas git lfs fetch --all might fetch 1000 GB of data. In such a case, do NOT include --all unless:
From git lfs fetch --help (emphasis added):
* --all:Download all objects that are referenced by any commit reachable from the refs provided as arguments. If no refs are provided, then all refs are fetched. This is primarily for backup and migration purposes. Cannot be combined with
--recentor--include/--exclude. Ignores any globally configured include and exclude paths to ensure that all objects are downloaded.
git lfs pullJust like git pull is the combination of git fetch and git merge, git lfs pull is the combination of git lfs fetch and git lfs checkout.
From git lfs pull --help (emphasis added):
git lfs pull [options] [<remote>]Download Git LFS objects for the currently checked out ref, and update the working copy with the downloaded content if required.
This is equivalent to running the following 2 commands:
git lfs fetch [options] [<remote>] git lfs checkout
So, that begs the question: "what does git lfs checkout do?":
git lfs checkoutThis command copies the git lfs files from your .git/lfs directory to your active, working tree for the current reference (branch or commit) you have currently checked-out.
From git lfs checkout --help:
Try to ensure that the working copy contains file content for Git LFS objects for the current ref, if the object data is available. Does not download any content; see
git lfs fetchfor that.Checkout scans the current ref for all LFS objects that would be required, then where a file is either missing in the working copy, or contains placeholder pointer content with the same SHA, the real file content is written, provided we have it in the local store. Modified files are never overwritten.
One or more
<glob-pattern>s may be provided as arguments to restrict the set of files that are updated. Glob patterns are matched as per the format described ingitignore(5).
And it provides some examples. Ex:
Examples
Checkout all files that are missing or placeholders:
$ git lfs checkoutCheckout a specific couple of files:
$ git lfs checkout path/to/file1.png path/to.file2.png
git lfs. I now recommend against using git lfs in our free GitHub reposfind, based on file size - see the example near the end, titled "(Figure out which file extensions to add to git lfs next)".git lfs info: