#!/bin/sh

PUB_KEY=~/.ssh/id_dsa.pub

usage()
{
    echo "usage: $(basename $0) [-k key] host" >&2
    exit 1
}

while getopts ":k:" c
do
    case "$c" in
    k)     PUB_KEY=~/.ssh/$OPTARG;;
    :|'?') usage;;
    esac
done
shift $(($OPTIND - 1))
[ $# -lt 1 ] && usage

cat $PUB_KEY | ssh $1 "mkdir -p ~/.ssh && cat >>~/.ssh/authorized_keys"
.