How to specify the private SSH-key to use when executing shell command on Git?

None of these solutions worked for me.

Instead, I elaborate on @Martin v. Löwis 's mention of setting a config file for SSH.

SSH will look for the user's ~/.ssh/config file. I have mine setup as:

Host gitserv
    Hostname remote.server.com
    IdentityFile ~/.ssh/id_rsa.github
    IdentitiesOnly yes # see NOTES below
    AddKeysToAgent yes

And I add a remote git repository:

git remote add origin git@gitserv:myrepo.git

(or clone a fresh copy of the repo with git@gitserv:myrepo.git as address)

And then git commands work normally for me.

git push -v origin master

If you have submodules, you can also execute the following in the repo directory, to force the submodules to use the same key:

git config url.git@gitserv:.insteadOf https://remote.server.com

NOTES

• The IdentitiesOnly yes is required to prevent the SSH default behavior of sending the identity file matching the default filename for each protocol. If you have a file named ~/.ssh/id_rsa that will get tried BEFORE your ~/.ssh/id_rsa.github without this option.

• AddKeysToAgent yes lets you avoid reentering the key passphrase every time.

• You can also add User git to avoid writing git@ every time.

References

• Best way to use multiple SSH private keys on one client
• How could I stop ssh offering a wrong key

Starting from Git 2.3.0 we also have the simple command (no config file needed):

GIT_SSH_COMMAND='ssh -i private_key_file -o IdentitiesOnly=yes' git clone user@host:repo.git

Note the -o IdentitiesOnly=yes is required to prevent the SSH default behavior of sending the identity file matching the default filename for each protocol as noted in the answer above.

Other people's suggestions about ~/.ssh/config are extra complicated. It can be as simple as:

Host github.com
  IdentityFile ~/.ssh/github_rsa

With git 2.10+ (Q3 2016: released Sept. 2d, 2016), you have the possibility to set a config for GIT_SSH_COMMAND (and not just an environment variable as described in Rober Jack Will's answer)

See commit 3c8ede3 (26 Jun 2016) by Nguyễn Thái Ngọc Duy (pclouds).
^{(Merged by Junio C Hamano -- gitster -- in commit dc21164, 19 Jul 2016)}

A new configuration variable core.sshCommand has been added to specify what value for GIT_SSH_COMMAND to use per repository.

core.sshCommand:

If this variable is set, git fetch and git push will use the specified command instead of ssh when they need to connect to a remote system.
The command is in the same form as the GIT_SSH_COMMAND environment variable and is overridden when the environment variable is set.

It means the git pull can be:

cd /path/to/my/repo/already/cloned
git config core.sshCommand 'ssh -i private_key_file' 
# later on
git pull

When cloning a new repo, where there is not yet any .git/config to modify, can first set it for just one command like git clone or git submodule add:

git -c core.sshCommand="ssh -i private_key_file" clone host:repo.git

Once the repo exists you can set the option permanently in the .git/config:

cd <repo or submodule you just cloned>
git config core.sshCommand "ssh -i private_key_file"

This is easier than setting a GIT_SSH_COMMAND environment variable, which, on Windows, as noted by Mátyás Kuti-Kreszács, would be

set "GIT_SSH_COMMAND=ssh -i private_key_file"

For all those commands, you can add a -o IdentitiesOnly=yes to limit SSH to the the private/public key you are specifying:

git config core.sshCommand 'ssh -i private_key_file -o IdentitiesOnly=yes' 
# or
git -c core.sshCommand="ssh -i private_key_file -o IdentitiesOnly=yes" clone host:repo.git
# or
set "GIT_SSH_COMMAND=ssh -i private_key_file -o IdentitiesOnly=yes"

gsullins suggests in the comments to adds to the .zshrc the following alias:

alias git.key1="git config core.sshCommand 'ssh -i <absolute path to private key>'"

As noted by Jaredo Mills in a comment:

One pitfall: if you mirror your repo to more than one host (Github, Gitlab), with different private keys, this method will send the wrong key.
The key is not associated with the repo, but with a username and hostname. ~/.ssh/config is the right place to get the association right, and it has the right matching capabilities for the job (see man ssh_config).

See HeyWatchThis's answer for illustration.

To sum up answers and comments, the best way to set up git to use different key files and then forget about it, which also supports different users for the same host (e.g. a personal GitHub account and a work one), which works on Windows as well, is to edit ~/.ssh/config (or c:\Users\<your user>\.ssh\config) and specify multiple identities:

Host github.com
HostName github.com
IdentityFile /path/to/your/personal/github/private/key
User dandv

Host github-work
HostName github.com
IdentityFile /path/to/your/work/github/private/key
User workuser

Then, to clone a project as your personal user, just run the regular git clone command.

To clone the repo as the workuser, run git clone git@github-work:company/project.git.

Contents of my_git_ssh_wrapper:

#!/bin/bash

ssh -i /path/to/ssh/secret/key $1 $2

Then you can use the key by doing:

GIT_SSH=my_git_ssh_wrapper git clone [email protected]:TheUser/TheProject.git

The problem is when you have different remote repositories on the same host (say github.com), and you want to interact with them using different ssh keys (i.e. different GitHub accounts).

In order to do that:

1. First you should declare your different keys in ~/.ssh/config file.

   # Key for usual repositories on github.com
   Host github.com
   HostName github.com
   User git
   IdentityFile ~/.ssh/id_rsa
   
   # Key for a particular repository on github.com
   Host XXX
   HostName github.com
   User git
   IdentityFile ~/.ssh/id_other_rsa
   

   By doing this you associate the second key with a new friendly name "XXX" for github.com.

2. Then you must change the remote origin of your particular repository, so that it uses the friendly name you've just defined.

   Go to your local repository folder within a command prompt, and display the current remote origin:

   >git remote -v
   origin  [email protected]:myuser/myrepo.git (fetch)
   origin  [email protected]:myuser/myrepo.git (push)
   

   Then change origin with:

   >git remote set-url origin git@XXX:myuser/myrepo.git
   >git remote -v
   origin  git@XXX:myuser/myrepo.git (fetch)
   origin  git@XXX:myuser/myrepo.git (push)
   

   Now you can push, fetch... with the right key automatically.

As stated here: https://superuser.com/a/912281/607049

You can configure it per-repo:

git config core.sshCommand "ssh -i ~/.ssh/id_rsa_example -F /dev/null"
git pull
git push

The fastest and simplest way of doing it is by:

Clone your repo with ssh:

git -c core.sshCommand="ssh -i ~/.ssh/<your_key>" clone [email protected]:<user>/<repo>.git

then cd into you cloned repo and:

git config core.sshCommand 'ssh -i ~/.ssh/<your_key>'

To test it's working:

git --git-dir=/path/to/repo/.git pull

So you may wonder: why my created ssh key does not work after I planted the .pub in github and the private is in the default directory?

The documentation gives us a command that clarifies the issue: ssh -vT [email protected]

The output shows a list of ssh keys names git looks for. So, you may want to create your key with one of those names, or use the above process to include the one you need.

GIT_SSH_COMMAND="ssh -i /path/to/git-private-access-key" git clone $git_repo

or

export GIT_SSH_COMMAND="ssh -i /path/to/git-private-access-key"
git clone REPO
git push

This command clones the repo and configures the SSH key to use permanently:

git clone -c "core.sshCommand=ssh -i ~/.ssh/<key>" [email protected]:<user>/<repo>.git

Now, if you run git fetch, git pull, or git push, it will use the SSH key configured in core.sshCommand (saved in .git/config).

Way better idea to add that host or ip to the .ssh/config file like so:

Host (a space separated list of made up aliases you want to use for the host)
    User git
    Hostname (ip or hostname of git server)
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/id_rsa_(the key you want for this repo)

From Git version 2.10.0, you can configure this per repo or globally

git config core.sshCommand "ssh -i ~/.ssh/id_rsa_example -o 'IdentitiesOnly yes'"

This will specify for the current repo what ssh key will use. I assume if you want to specify this global only need to set the --global option.

I went with the GIT_SSH environment variable. Here's my wrapper, similar to that from Joe Block from above, but handles any amount of arguments.

File ~/gitwrap.sh

#!/bin/bash
ssh -i ~/.ssh/gitkey_rsa "$@"

Then, in my .bashrc, add the following:

export GIT_SSH=~/gitwrap.sh

I just needed to add the key and then rerun the git clone.

ssh-add ~/.ssh/id_rsa_mynewkey
eval $(ssh-agent -s)
git clone [email protected]:mycompany/myrepo.git

If none of the other solutions here work for you, and you have created multiple ssh-keys, but still cannot do simple things like

git pull

then assuming you have two ssh key files like

id_rsa
id_rsa_other_key

then inside of the git repo, try:

# Run these commands INSIDE your git directory
eval `ssh-agent -s`
ssh-add ~/.ssh/id_rsa
ssh-add ~/.ssh/id_rsa_other_key

and also make sure your github default username and userid are correct by:

# Run these commands INSIDE your git directory
git config user.name "Mona Lisa"
git config user.email "[email protected]"

See https://gist.github.com/jexchan/2351996 for more more information.

2021. If you're on a Mac.

Say you have an ubuntu server on aws, which you normally connect to like this:

% ssh -i blah/yourkeypair.pem [email protected]

In terminal just

% export GIT_SSH_COMMAND="ssh -i /Users/fattie/Desktop/blah/yourkeypair.pem"

After you have done that. You can then freely ...

% git clone [email protected]:/home/ubuntu/teste.git  

That will clone the repo on your server to your local folder "teste",

you can then freely when in teste/ do the usual commands such as ...

% git push origin master

and so on.

--

Note also: https://stackoverflow.com/a/67287133/294884

As for on the server, it seems you basically

] git clone --bare the-actual-folder teste.git

and then in teste.git

] git init --bare --shared

When you need to connect to github with a normal request (git pull origin master), setting the Host as * in ~/.ssh/config worked for me, any other Host (say, "github" or "gb") wasn't working.

Host *
    User git
    Hostname github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/id_rsa_xxx

Many of these solutions looked enticing. However, I found the generic git-wrapping-script approach at the following link to be the most useful:

How to Specify an ssh Key File with the git command

The point being that there is no git command such as the following:

git -i ~/.ssh/thatuserkey.pem clone [email protected]:/git/repo.git

Alvin's solution is to use a well-defined bash-wrapper script that fills this gap:

git.sh -i ~/.ssh/thatuserkey.pem clone [email protected]:/git/repo.git

Where git.sh is:

#!/bin/bash

# The MIT License (MIT)
# Copyright (c) 2013 Alvin Abad
# https://alvinabad.wordpress.com/2013/03/23/how-to-specify-an-ssh-key-file-with-the-git-command

if [ $# -eq 0 ]; then
    echo "Git wrapper script that can specify an ssh-key file
Usage:
    git.sh -i ssh-key-file git-command
    "
    exit 1
fi

# remove temporary file on exit
trap 'rm -f /tmp/.git_ssh.$$' 0

if [ "$1" = "-i" ]; then
    SSH_KEY=$2; shift; shift
    echo "ssh -i $SSH_KEY \$@" > /tmp/.git_ssh.$$
    chmod +x /tmp/.git_ssh.$$
    export GIT_SSH=/tmp/.git_ssh.$$
fi

# in case the git command is repeated
[ "$1" = "git" ] && shift

# Run the git command
git "$@"

I can verify that this solved a problem I was having with user/key recognition for a remote bitbucket repo with git remote update, git pull, and git clone; all of which now work fine in a cron job script that was otherwise having trouble navigating the limited-shell. I was also able to call this script from within R and still solve the exact same cron execute problem (e.g. system("bash git.sh -i ~/.ssh/thatuserkey.pem pull")).

Not that R is the same as Ruby, but if R can do it... O:-)

A lot of good answers, but some of them assume prior administration knowledge.

I think it is important to explicitly emphasize that if you started your project by cloning the web URL - https://github.com/<user-name>/<project-name>.git
then you need to make sure that the url value under [remote "origin"] in the .git/config was changed to the SSH URL (see code block below).

With addition to that make sure that you add the sshCommmand as mentioned below:

user@workstation:~/workspace/project-name/.git$ cat config
[core]
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
    sshCommand = ssh -i ~/location-of/.ssh/private_key -F /dev/null <--Check that this command exist
[remote "origin"]
    url = [email protected]:<user-name>/<project-name>.git  <-- Make sure its the SSH URL and not the WEB URL
    fetch = +refs/heads/*:refs/remotes/origin/*
[branch "master"]
    remote = origin
    merge = refs/heads/master

Read more about it here.

If you are getting an SSH permission denied Error when running commands like git push, pull, or fetch even after you have copied your SSH public key to GitHub.

NOTE
Use --local when you're in a local git repo,
but use --global when you want to apply to all repos

Use this:

git config --add --local core.sshCommand 'ssh -i /path-to-ssh-private-key'

E.g

git config --add --local core.sshCommand 'ssh -i /home/user/.ssh/github-key'

You're done!

Optionally you can verify your change with this:

git config --local --get core.sshCommand

Why don't you just add location of identity key to git config file for a particular repo like this:

cd .git

vi config

[core]
    sshCommand = ssh -i <IDENTITY_KEY_LOCATION> -o IdentitiesOnly=yes

That's all you need.

if you have directory on your path where you want to sign with a given identifyfile you can specify to use a specific identify file via the .ssh/config file by setting the ControlPath e.g.:

host github.com
  ControlPath ~/Projects/work/**
  HostName github.com
  IdentityFile ~/.ssh/id_work
  User git

Then ssh will use the specified identity file when doing git commands under the given work path.

In my case I've got two accounts with different ssh keys. I wanted to clone a repository, so how i did it:

id_ed25519 - is the name of second key, usually default key is: ~/.ssh/id_rsa

$ eval `ssh-agent -s`

$ ssh-add ~/.ssh/id_ed25519

If you use a Github you can check correct auth with command below:

$ ssh -T -p 443 [email protected]

Clone or Pull code with command below:

(for the first time)

$ git clone [email protected]:username/path-somewhere.git

(for the next time)

$ git pull

Clone in one command

git -c core.sshCommand='ssh -i /path/to/key/' clone [email protected]:your_repository.git /path/target/clone --branch git_branch_name

Also, as a simple "workaround", if you don't really need it that often:

Remove all ssh identities from the currently running ssh agent (not physically).

ssh-add -D

Re-add the one you need to work with to your currently running ssh-agent

ssh-add ~/.ssh/MyProperProfile

Do the gits

Optionally - revert by adding other identities (or all of 'em).

In Windows with Git Bash you can use the following to add a repository

ssh-agent bash -c 'ssh-add "key-address"; git remote add origin "rep-address"'

for example:

ssh-agent bash -c 'ssh-add /d/test/PrivateKey.ppk; git remote add origin [email protected]:test/test.git'

Which private key is in drive D, folder test of computer. Also if you want to clone a repository, you can change git remote add origin with git clone.

After enter this to Git Bash, it will ask you for passphrase!

Be Aware that openssh private key and putty private key are different!

If you have created your keys with puttygen, you must convert your private key to openssh!

Most of the answers given here do not explain the details for the most basic usage.

After you have setup a server (in this case a linux server) in the cloud, you connect to it using ssh from the terminal.

From your computer, add the private key dyson-ubuntu-vm.pem which is given to you by your cloud services provider such as Azure, AWS etc to your .ssh configuration on your local machine like this:

Copy the .pem file to the /home/ssenyonjo/.ssh folder, then open /home/ssenyonjo/.ssh/config file and add the following entry:

Host 20.85.213.44
  HostName 20.85.213.44
  User Dyson
  IdentityFile /home/ssenyonjo/.ssh/dyson-ubuntu-vm.pem
  IdentitiesOnly yes

Now from your terminal, access the cloud linux server like so:

ssh [email protected]

When that works, create a git project on the cloud server like so:

Dyson@dyson-ubuntu-vm:~/projects$ git init --bare s2

Now come back to your local machine and clone that empty repository like so:

ssenyonjo@ssenyonjo-pc:~/Projects/mastering-git$ git clone ssh://[email protected]/home/Dyson/projects/s2

If you see an error that looks something like: fatal: Could not read from remote repository, It means you're accessing the wrong folder. Ensure you have outlined the right path from the root to the created repository.

If you dont want to setup a config file but want to access the ssh server that requires a key, you can use below command:

GIT_SSH_COMMAND='ssh -i ~/Projects/aws/keys/aws_ubuntu.pem'  git clone ssh://[email protected]/home/ubuntu/projects/mastering-git/rand 

You can export the command to continue using it for other tasks like git push and git pull

export GIT_SSH_COMMAND='ssh -i ~/Projects/aws/keys/aws_ubuntu.pem'

See: https://stackoverflow.com/a/29754018/10030693

To have GIT_SSH_COMMAND environment variable work under Windows(CMD) instead of:

set GIT_SSH_COMMAND="ssh -i private_key_file"

Use:

set "GIT_SSH_COMMAND=ssh -i private_key_file"

The quote has to be like

set "variable=value" 

Some backgorund: https://stackoverflow.com/a/34402887/10671021