ssh-copy.sh

#!/usr/bin/env bash
usage() { cat <<- DOCUMENT

    $PROGNAME [-h] [-t] [-k key] [-l login] [server]

    Utility for automatically exporting ssh keys into remote servers for authentication.
    Checks $HOME/.ssh for id_rsa.pub or id_dsa.pub and appends them into
    the authorized_keys of remote host

    AUTHOR:     Sang Han
    YEAR:       2013
    VERSION:    2.4

    -h [help]
        Outputs usage directions
    -t [test]
        Runs unit tests
    -k [key]
        Specify your own public key located in $HOME/.ssh directory
    -l [login]
        Specify user login credentials


	DOCUMENT
}

# Global Variables
PROGNAME="$(basename "$0")"

function error_exit() {
    printf "ERROR due to %s"  "${1:-"Unknown Error"}"
    exit 1
}

function test_variables() {
    declare -a variables=(${*})
    for var in "${variables[@]}"; do
        printf "%30s = %s\n" \
            "$(tput setaf 9)\$${var}$(tput sgr0)" \
            "$(tput setaf 3)${!var}$(tput sgr0)"
    done
}

function install_keys() {
    # Reads the public key file with cat and then logs into ssh server
    # and appends the public key file at the end of the authorized_key file
    # within $HOME
    < "${PUBKEY[i]}" ssh -l "$LOGIN_USER" "$SERVER" \
        'mkdir -p ~/.ssh && chmod 0700 ~/.ssh && tee -a ~/.ssh/authorized_keys'
}

function check_keys() {
    # Checks $HOME/.ssh directory for default keys
    [[ -n $(find ~/.ssh -maxdepth 1 -name '*.pub' -print -quit) ]] \
        || error_exit "missing ssh public keys"
}

function check_auth() {
    # Checks if proper credentials have been given as $1. After credential has
    # been checked, will read and bind the variable.
    local CREDENTIAL=$1
    if [[ ! ${!CREDENTIAL} ]]; then
        read -p "${CREDENTIAL}:  " "${CREDENTIAL}"
    fi
}

function check_server() {
    SERVER=$1
    if [[ "$SERVER" =~ @ ]]; then
        LOGIN_USER=${SERVER%@*}
        SERVER=${SERVER#*@}
        return
    fi
}

main() {
    # Default Public Keys
    if [ -z $KEY ]; then declare -a KEY=("id_rsa" "id_dsa"); fi

    for (( i=0; i<${#KEY[@]}; i+=1 )); do
        local PUBKEY[i]="$HOME/.ssh/${KEY[i]}.pub"

        # Test Keys
        if ((TEST==1)); then test_variables KEY[i] PUBKEY[i]; continue; fi

        # Gather necessary login credentials
        if [[ -r "${PUBKEY[i]}" ]]; then
            check_auth LOGIN_USER; check_auth SERVER
            install_keys && break
        fi
    done
}

# Option Parsing
declare -i TEST=0
while getopts ":k:l:th" OPTION; do
    case $OPTION in
        h) usage
           exit 0
            ;;
        k) KEY=$OPTARG
            ;;
        t) TEST=1
            ;;
        l) LOGIN_USER=$OPTARG
            ;;
        ?) { echo "Invalid option: -${OPTARG}"; usage; } >&2
            exit 1
            ;;
    esac
done
    shift $((OPTIND-1))

if [[ "$0" == "${BASH_SOURCE}" ]]; then
    # Validate user input
    if [ $# = 1 ]; then check_server "$1"; fi; check_keys

    # Test Globals
    if ((TEST==1)); then test_variables SERVER LOGIN_USER; fi

    main
fi

< "${PUBKEY[i]}" ssh -l "$LOGIN_USER" "$SERVER" \
    'mkdir -p ~/.ssh && chmod 0700 ~/.ssh && tee -a ~/.ssh/authorized_keys'

Very nice! +1