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I recently reinstalled my laptop and found that 'git clone' wasn't working. I was consistently receiving Permission denied (publickey). errors.

The fix is documented on GitHub's SSH issues page: use ssh-add to tell SSH about the key I want to use to authenticate on GitHub.

My question is: under the hood, what does ssh-add actually do?

I've been meaning to expand my understanding of SSH for a while, & this seems like a good excuse to start :-)

Duncan Bayne
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2 Answers2

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ssh-add adds private key identities (from your ~/.ssh directory) to the authentication agent (ssh-agent), so that the ssh agent can take care of the authentication for you, and you don’t have type in passwords at the terminal.

Peter John Acklam
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Based on this article in github, sometime on some linux distributions even after you set up everything properly this error shows up:

Agent admitted failure to sign using the key.
debug1: No more authentication methods to try.
Permission denied (publickey).

And you should run ssh-add to solve the issue.

Jens Erat
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Sadegh
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