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Transfer SSH public key to another machine in one step

Terminal - Transfer SSH public key to another machine in one step
ssh-keygen; ssh-copy-id user@host; ssh user@host
2009-03-18 07:59:33
User: bwoodacre
Functions: ssh ssh-keygen
Transfer SSH public key to another machine in one step

This command sequence allows simple setup of (gasp!) password-less SSH logins. Be careful, as if you already have an SSH keypair in your ~/.ssh directory on the local machine, there is a possibility ssh-keygen may overwrite them. ssh-copy-id copies the public key to the remote host and appends it to the remote account's ~/.ssh/authorized_keys file. When trying ssh, if you used no passphrase for your key, the remote shell appears soon after invoking ssh user@host.


There are 2 alternatives - vote for the best!

Terminal - Alternatives

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yes, but you missed some params in ssh-keygen for passwordless prompt nothing.

ssh-keygen -t rsa -f ~/.ssh/id_rsa -b 2048 -P
Comment by starchox 314 weeks and 5 days ago

@starchox you have specified the default values for the -t -f and -b options so they aren't necessary assuming a recent ssh-keygen. To truly get everything to run unattended (which probably isn't a "best practice") without a passphrase, try

ssh-keygen -P ''; ssh-copy-id -i ~/.ssh/id_rsa user@host; ssh user@host

that's two single quotes after the -P setting the passphrase to an empty string which I believe should be the same as no passphrase at all.

Comment by bwoodacre 309 weeks ago

I think what starchox was trying to say it that in order to be not prompted at all you have to specify everything his command did; and more, actually...

ssh-keygen -P '' -f ~/.ssh/id_rsa -b 2048

...will not ask you for a thing.


your second command doesn't need the -i in it, that is the default (and without prompt)

So, for most of you out there, if you are doing this on a new machine or machine that otherwise needs a new key to be written, your command for doing everything you need (without a passphrase) on one line is:

ssh-keygen -P '' -f ~/.ssh/id_rsa -b 2048; ssh-copy-id user@host; ssh user@host

...ssh user@host is obviously only for logging in when done

...and most systems don't prompt for the -b (bits) and default to 2048


Comment by sudopeople 304 weeks and 5 days ago

Your point of view

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