#!/usr/bin/env ruby
require 'rubygems'
require 'net/ssh'

$keyfile = "/Users/nate/.ssh/mypubkey.pub"
$connect_host = "somehost.com"

# Determines whether an ~/.ssh directory exists on the client side
def remote_ssh_directory_exists?(connection)
  output = ""
  cmd_check_ssh = "test -e ~/.ssh && echo 1"
  connection.exec!(cmd_check_ssh) do |ch, stream, data|
    output << data if stream == :stdout
  end
  output.chomp == "1"
end

def remote_authorized_key_file_exists?(connection)
  output = ""
  cmd_check_keyfile = "test -e ~/.ssh/authorized_keys && echo 1"
  connection.exec!(cmd_check_keyfile) do |ch, stream, data|
    output << data if stream == :stdout
  end
  output.chomp == "1"
end

# Creats an authorized key file (.ssh/authorized_keys) on the remote host
def create_authorized_keys_file(connection, stdout)
  connection.exec!("touch ~/.ssh/authorized_keys")
  stdout << "- Created ~/.ssh/authorized_keys\n"
end

begin
  print "Enter username to connect at host (e.g 'nate'@somehost.com) ->"
  uname = gets.chomp
  print "Remote password ->"
  pwd = gets.chomp
  local_key = open($keyfile) { |f| f.read }  
  stdout = ""
  
  Net::SSH.start($connect_host, uname, :password => pwd) do |ssh|    
    if remote_ssh_directory_exists?(ssh)
      stdout << "- Dependency: SSH folder exists [yes]\n"
      # check if the authorized_keys file exists
      if remote_authorized_key_file_exists?(ssh)
        stdout << "- Dependency: authorized_keys exists [yes]\n"
      else
        stdout << "- Dependency: authorized_keys exists [no]\n"
        create_authorized_keys_file(ssh, stdout)
      end
    else
      stdout << "- Dependency: SSH folder exists [no]\n"
      ssh.exec!("mkdir ~/.ssh")
      stdout << "- Created .ssh folder\n"
      create_authorized_keys_file(ssh, stdout)
    end
    
    ssh.exec!("echo \"#{local_key}\" >> ~/.ssh/authorized_keys") 
    stdout << "- Added key to file [yes]"
  end
  puts stdout
end

Script for posting SSH keys to a remote host

ssh

Ruby