How to run ssh-add on windows?

Question

Original answer using git's start-ssh-agent

Make sure you have Git installed and have git's cmd folder in your PATH. For example, on my computer the path to git's cmd folder is C:\Program Files\Git\cmd

Make sure your id_rsa file is in the folder c:\users\yourusername\.ssh

Restart your command prompt if you haven't already, and then run start-ssh-agent. It will find your id_rsa and prompt you for the passphrase

Update 2019 - A better solution if you're using Windows 10: OpenSSH is available as part of Windows 10 which makes using SSH from cmd/powershell much easier in my opinion. It also doesn't rely on having git installed, unlike my previous solution.

1. Open Manage optional features from the start menu and make sure you have Open SSH Client in the list. If not, you should be able to add it.

2. Open Services from the start Menu

3. Scroll down to OpenSSH Authentication Agent > right click > properties

4. Change the Startup type from Disabled to any of the other 3 options. I have mine set to Automatic (Delayed Start)

5. Open cmd and type where ssh to confirm that the top listed path is in System32. Mine is installed at C:\Windows\System32\OpenSSH\ssh.exe. If it's not in the list you may need to close and reopen cmd.

Once you've followed these steps, ssh-agent, ssh-add and all other ssh commands should now work from cmd. To start the agent you can simply type ssh-agent.

6. Optional step/troubleshooting: If you use git, you should set the GIT_SSH environment variable to the output of where ssh which you ran before (e.g C:\Windows\System32\OpenSSH\ssh.exe). This is to stop inconsistencies between the version of ssh you're using (and your keys are added/generated with) and the version that git uses internally. This should prevent issues that are similar to this

Some nice things about this solution:

• You won't need to start the ssh-agent every time you restart your computer
• Identities that you've added (using ssh-add) will get automatically added after restarts. (It works for me, but you might possibly need a config file in your c:\Users\User\.ssh folder)
• You don't need git!
• You can register any rsa private key to the agent. The other solution will only pick up a key named id_rsa

Hope this helps

One could install Git for Windows and subsequently run ssh-add:

Step 3: Add your key to the ssh-agent

To configure the ssh-agent program to use your SSH key:

If you have GitHub for Windows installed, you can use it to clone repositories and not deal with SSH keys. It also comes with the Git Bash tool, which is the preferred way of running git commands on Windows.

1. Ensure ssh-agent is enabled:

   • If you are using Git Bash, turn on ssh-agent:

     # start the ssh-agent in the background
     ssh-agent -s
     # Agent pid 59566
     

   • If you are using another terminal prompt, such as msysgit, turn on ssh-agent:

     # start the ssh-agent in the background
     eval $(ssh-agent -s)
     # Agent pid 59566
     

2. Add your SSH key to the ssh-agent:

   ssh-add ~/.ssh/id_rsa
   

If you are not using GitBash - you need to start your ssh-agent using this command

start-ssh-agent.cmd

If your ssh agent is not set up, you can open PowerShell as admin and set it to manual mode

if( ($startupType =(Get-Service -Name ssh-agent | Select-Object -Property StartupType).StartupType) -ne  [System.ServiceProcess.ServiceStartMode]::Manual){
    if((Get-Service -Name ssh-agent | Select-Object -Property Status ).Status -ne [System.ServiceProcess.ServiceControllerStatus]::Running){
        Get-Service -Name ssh-agent | Set-Service -StartupType Manual
        Start-Sleep -Milliseconds 300 # Wait for the service host to respond before fiddling with it
        Start-Service -Name ssh-agent
        Get-Service -Name ssh-agent | Get-Process
    }
} else {
    Start-Service -Name ssh-agent
}

If you are trying to setup a key for using git with ssh, there's always an option to add a configuration for the identity file.

vi ~/.ssh/config

Host example.com
IdentityFile ~/.ssh/example_key

2021 Answer

Microsoft has improved ssh-key support in recent years. There is now a full featured "service" to run.

From https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_keymanagement

In (Admin) Powershell:

# By default the ssh-agent service is disabled.
Get-Service -Name ssh-agent | Set-Service -StartupType Automatic

Start-Service ssh-agent

Then from any user shell:

ssh-add path/to/.ssh/id_rsa

I have been in similar situation before. In Command prompt, you type 'start-ssh-agent' and voila! The ssh-agent will be started. Input the passphrase if it asked you.