SSH Authorized Keys – How to Get All Fingerprints

awkbashsshssh-keygenssh-keys

Is there a simple way to get a list of all fingerprints entered in the .ssh/authorized_keys || .ssh/authorized_keys2 file?

ssh-keygen -l -f .ssh/authorized_keys

will only return fingerprint of first line / entry / publickey

hack with awk:

awk 'BEGIN { 
    while (getline < ".ssh/authorized_keys") {
        if ($1!~"ssh-(r|d)sa") {continue}
        print "Fingerprint for "$3
        system("echo " "\""$0"\"> /tmp/authorizedPublicKey.scan; \
            ssh-keygen -l -f /tmp/authorizedPublicKey.scan; \
            rm /tmp/authorizedPublicKey.scan"
        )
    }
}'

but is there an easier way or ssh command I didn't find?

Best Answer

Here's another hack using plain bash without temporary files:

while read l; do
  [[ -n $l && ${l###} = $l ]] && ssh-keygen -l -f /dev/stdin <<<$l;
done < .ssh/authorized_keys

You can easily make it a function in your .bashrc:

function fingerprints() {
  local file="${1:-$HOME/.ssh/authorized_keys}"
  while read l; do
    [[ -n $l && ${l###} = $l ]] && ssh-keygen -l -f /dev/stdin <<<$l
  done < "${file}"
}

and call it with:

$ fingerprints .ssh/authorized_keys
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