#!/bin/bash
# Default command anyterm will run.
# Simply prompt the user for a username and 
# ssh locally as that user

set -eo pipefail

while : ; do
    echo -n "Username: "
    read U
    if [[ -z "$U" ]]; then
	echo "Disconnecting."
	exit
    fi
    # Make sure it does not start with a "-" and only contains valid
    # username characters.
    if [[ "$U" =~ ^[A-Za-z0-9_][A-Za-z0-9_-]*$ ]]; then
	cd ~

	if [[ ! -e .ssh/known_hosts ]]; then
	    mkdir -p --mode=700 .ssh
	    for k in /etc/ssh/ssh_host_{rsa,dsa}_key.pub; do
		if [[ -r "$k" ]]; then
		    echo -n "localhost.localdomain "
		    cat "$k"
		fi
	    done >.ssh/known_hosts
	fi

	ssh -l "$U" localhost.localdomain" || :
    else
	echo "Bad username."
    fi
done