Put the public ssh key file to various remote hosts to use certificate based authentication

ssh-put-key.sh

#!/bin/bash

if [ $# -eq 0 ]; then
        me=$(basename $0)
        echo "-> copy the personal rsa key to other machines for certificate based authentication"
        echo Usage:
        echo "$me [user@]machine [[user@]machine [...]]"
fi


cert_var=_ssh_key_file
cert_var=$USER$cert_var
cert_ext=.pub


cert=${!cert_var}
if [ ! "$cert" ]; then
        cert=~/.ssh/id_rsa
        echo "using default key $cert"
        echo "export $cert_var=/path/to/key/file to override"
fi

pubkey=$cert$cert_ext

if [ ! -f $cert ];then
        echo Key-Pair $cert does not exist. Creating...
        ssh-keygen -N "" -f $cert
fi

for arg in "$@"; do
        echo Machine $arg:
        ssh-copy-id -i $pubkey "$arg"
        echo --------------------------------
done