Linux Rsync Backup

Here is a first cut at a backup script which will pull from a linux host. It will create an SSH public key pair if none exists already, copy them to the Pre, then perform a complete rsync to the user's ~/palm directory. So far it works okay with the emulator.

Warning - Setting up a key pair in this manner will mean a user on your linux box can get your Pre as well.

Instructions

• Make sure you have rsync and openssh installed on your Linux box.
• Save the code below to a file on your linux box (eg, backup).
• Make it executable (eg, chmod a+x backup.
• Enable wifi on your Pre (you'll need its current IP address), or start your emulator.
• To try with your emulator

linuxbox$ ./backup localhost 5522 root
found, using it
reached the palm with ssh key
receiving file list ... done
./
bin/
... etc ...

• To run with the Pre over IP:

 linuxbox$ ./backup 111.222.233.244 222 root

Note you may need to specify the user you created when you rooted the Pre instead. The user will need read access to the whole file tree.

Code

#!/bin/bash

die() 
{
    echo $@
    exit 1;
}

[ $# -eq 3 ] || die "Usage: $0 palm_ip palm_port palm_user"
host=$1
port=$2
user=$3

strict='-o StrictHostKeyChecking=no'
pubkey='-o PreferredAuthentications=publickey'
dest="-p $port $user@$host"

[ -x /usr/bin/rsync ] || die no rsync, you should: sudo apt-get install rsync

if [[ ! -f ~/.ssh/id_dsa || ! -f ~/.ssh/id_dsa.pub ]]; then
    echo we need to make an ssh keypair
    ssh-keygen -q -t dsa -f ~/.ssh/id_dsa -N '' || die ssh-keygen failed
else
    echo found, using it
fi

if ssh $strict $pubkey $dest ls /etc/palm > /dev/null; then
    echo reached the palm with ssh key
else
    echo need to copy local pubkey to palm
    cmd='umask 077; test -d .ssh || mkdir .ssh ; cat >> .ssh/authorized_keys'
    cat ~/.ssh/id_dsa.pub | ssh $strict $dest $cmd

    if ssh $strict $pubkey $dest ls /etc/palm > /dev/null; then
	echo second try good, reached the palm with ssh key
    else
	die could not use pubkey after installing it on the palm
    fi
fi

rsync -avz --size-only --exclude proc/ --exclude dev/ --exclude sys/ \
    -e "ssh -p $port $strict" $user@$host:/ ~/palm