ssh-auto-auth.sh

#!/bin/sh

#######################################################
#
# Precondition: Complete executing the following command
#       ssh-keygen -t rsa
# 
# How to use: 
#       sh ssh-auto-auth.sh {user name}@{IP address}
#
#       ex. sh ssh-auto-auth.sh root@192.168.1.1
#
# FYI: 
#       http://www.linuxproblem.org/art_9.html 
#
#######################################################

if [ $# -lt 1 -o $# -gt 1 ]; then
    echo -e "How to use: sh ssh-auto-auth.sh {user name}@{IP address}"
    exit 1
fi

# Use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine).
ssh "$1" mkdir -p .ssh

if [ $? -ne 0 ]; then
    echo -e "Failed to create .ssh directory."
    exit 1
fi

# Append a's new public key to b@B:.ssh/authorized_keys and enter b's password one last time.
cat ~/.ssh/id_rsa.pub | ssh "$1" 'cat >> .ssh/authorized_keys'

if [ $? -ne 0 ]; then
    echo -e "Failed to append new public key to authorized_keys"
    exit 1
fi

echo "Complete!"
exit 0