#! /bin/sh

# Question 9:

#  Modify your answer to question 7 so that your program will:

# o source the keychain information about where your agent is;
# o use the rsync program to copy the contents of the directory
#   ~/public_html to the directory ~/public_html-backup in your own
#   account on another computer.

#  For example, if your local account contains the file
#  ~/public_html/important.html, then the file
#  ~/public_html-backup/important.html will be created on the remote
#  computer if it does not exist, and the content will be identical on
#  both machines. 

prog=$(basename $0)

usage() {
    cat <<EOF
Usage: $prog remote_machine
where remote_machine is the IP address or hostname of a remote
computer.  This program will transfer ~/public_html to the directory
~/public_html-backup on the remote computer.
EOF
    exit 1
}

[ $# -eq 1 ] || usage;
remote=$1
[ -z "$remote" ] && usage;

uid_num=$(id -u)

lockfile="/tmp/${prog}.lock"
[ "$uid_num" -eq 0 ] && lockfile=/var/lock/subsys/${prog}.lock

signal_handler() {
    echo "received a signal; terminating"
    rm -f $lockfile
    exit 1
}

[ -r ~/.keychain/${HOSTNAME}-sh ] || {
    echo "No keychain filename; exiting";
    exit 1
}

if [ -e "$lockfile" ]
then
    echo "lockfile exists"
    exit 1
else
    trap signal_handler INT TERM HUP QUIT
    touch $lockfile
    [ -e $lockfile ] || { echo "$prog: cannot create $lockfile"; exit 1; }
fi

source ~/.keychain/${HOSTNAME}-sh
rsync -avz -e ssh ~/public_html/ ${remote}:public_html-backup

rm -f $lockfile