#! /bin/sh

# O Muse! We begin
# with ancient incantations
# to sing our song well.

# (It means, 'use this shell.'
# I know it looks funny, but 
# UNIX is like that.)

# Cryptic UNIX strings
# like "hash bang slash bin slash sh"
# save keystrokes, and wrists.

# No one likes typing
# the same thing over and over,
# so files get short names.

# Take these hashes (please!)
# adorning my measured lines:
# they say, comments here!

# This is a shell script.
# It moves files from place to place,
# backups = peace of mind.

# (I know I cheated 
# there; keystrokes and syllables
# are in short supply.

# O muse, we'll never
# get anywhere if I can't 
# use symbols, forgive.)


# Onward we must go.
# Line by line, the file is read;
# No GOTO 10 here.

# These lines are for you,
# dear reader; the shell doesn't
# read our verse.  Pity.

# Let's start at the top.
# I use this script, it's for me;
# Your miles WILL vary.

# (I run on a Mac.
# Linux users might find the
# filenames quite strange.

# But Macs run UNIX!
# Darwin kernel with launchd;
# hark, the angels sing.)

# A universal
# truth, like land wars in Asia:
# all drives will fail.

# But Moore's Law saves us.
# You can get hard drives for less
# than a good latte.

# Simple strategy:
# Toss your data to the wind,
# across many disks.  

# Onsite, offsite, pshaw!
# They're all the same to our law.
# Enough rhymes! Let's talk.

# Backups are snapshots
# of a host through time. One's good;
# three is divine.

# Archives lack a host.
# Like Goa'uld or Trill, they
# live on network drives.

# Mirrors do their task,
# spreading data around like
# beads at mardi gras.

# You could also say
# Archives are fixed, permanent;
# Backups use --delete.

# So: three drives you need.
# Backup should be big, Archive
# and Mirror equal.


# Did I mention speed?
# Get Firewire or we'll
# be at this all day.

# There are two flavors
# (sweet!) of this fast protocol:
# Four hundred, and eight.

# USB 2's fine
# if that's all your machine has.
# 1.1's too slow.

# I know how this sounds.
# Trust me, though.  You've more data
# than even you know.


# Let's declare our terms,
# give our chant some form and flow
# (and keep our typing --)

tdy=`date +%Y-%m-%d`
host=`hostname -s`
user=`id -un`

# Did you notice it?
# No apostrophes for us!!
# Look under the ~ --

# Backticks tell UNIX
# 'take this output as a string'
# `command me, oh muse.`

# Now let's name our drives.
# We'll use these later, when we
# see if they're attached.

adrive=/Volumes/Archive
bdrive=/Volumes/Backup
mdrive=/Volumes/Mirror
sdrive=/Volumes/Secure

# See?  That wasn't hard.
# I'm a better poet than
# programmer.  (You're doomed.)

# Now on to backups.
# Set your drive structure up here.
# (Brute force, save the day!)

# My backup drive
# is > 3x my laptop's size.
# So I'll arrange it so:

backup=$bdrive/$host/
last=$backup/Users/
old=$bdrive/Old/$host/Users/
older=$bdrive/Older/$host/Users/

# Why use $host? Easy:
# Other machines use this drive.
# $host keeps them apart.

excludes=~/bin/backup/excludes

# "excludes" is a file
# that we'll use later on to
# step around problems.

use_offsite=yes
offsite=~/bin/backup/offsite

# Our variables,
# I do declare, are declared.
# Whitman would be proud.

# Before we go on,
# check the map to see what's there.
# "if test" is my friend.

if test -d $bdrive
then 
    if test -d $old
	then # move 1 into 2

	# For backups, rsync
	# does what we need; only changes
        # are replicated.

        # We're moving things back
        # from old to older (brute force)
        # No elegance here.

        mkdir -p $older
	rsync -avzx -E --progress --delete $old $older	

	# A word on those flags:
	# "archive, verbose, zip, stay here,"
	# and "secret Mac stuff."

	# "Dash e" and "dash E"
	# weren't separated at birth.
	# Homonyms, that's all.

	# Resource forks are hell
	# when going across systems.  
	# Black magic, I guess.

        # So "dash E" for Macs
        # on journaled HFS+
        # volumes only, please.

	# What were we doing?  
	# Oh right, backing up data.
	# Oldest stuff's now gone.

    fi

	# Let's do it again!
	# Moving through time is easy,
	# one direction only.

        # Last backup's so then,
	# get it out of our sight. To
	# Old/ it goes, cruel eld.

    if test -d $backup

	then 
	mkdir -p $old
	rsync -avzx -E --progress --delete $last $old

        # Did you follow that?
        # Watch: "Last" goes to "Old" goes to
	# "Older" goes to ... null.

	# (If I were clever
	# I'd come up with better names,
        # but this works for me.

        # Important advice:
	# know when good is good enough.
	# Move on with your life.)

    fi

    # Now on to our drive.
    # Duplicate precious data!
    # (finally, you sigh.)
        
    rsync -avzx -E --progress --delete --exclude-from $excludes / $backup

    # OMG we're done?
    # I never thought we'd get here:
    # "Backup is complete."

    echo "Backup is complete."	

fi

# If $bdrive's not there
# you skipped that whole bit; don't fret.
# There's always next time.

# Now it's archive time.
# We'll check to make sure it's there
# before we go on.

if test -d $adrive
then

    # Mirror mirror on
    # the wall, did you ever think
    # you'd reflect bytes?

    if test -d $mdrive
    then 

      rsync -avzx -E --progress --exclude ".Trashes/" --exclude ".Spotlight-V100/" --delete $adrive $mdrive


    # That's it for Mirror.
    # What can I say?  It has one 
    # purpose:  Save Archive.

    # You may ask yourself,
    # why are we mirroring now?
    # Two words: "Murphy's Law."

    fi

  # This next bit's easy.
  # Although, I've said that before.
  # (Perhaps I was wrong?)

  # All my archive scripts
  # dump their output in one
  # location: ~/Archive/

  # So here at the end
  # it doesn't matter what's run,
  # we just grab it all.

  rsync -avz -E --progress ~/Archive/ $adrive/ 

  # Our media is next,
  # separate copies we'll keep.
  # (Again, no --delete.) 

  rsync -avz -E --progress --exclude "Podcasts/" ~/Music/iTunes $adrive/Media/
# rsync -avz -E --progress ~/Pictures/iPhoto\ Library $adrive/Media/
  rsync -avz -E --progress ~/Sites/myPhoto/iPhoto\ Library $adrive/Media/

fi

# That's it.  We are done.
# Data scattered like petals.
# I thank you, O muse.






# 2007-03-22: Version 1.0 published.
# Referenced at http://brettpeters.org/docs/backup.html.  
# (c) Brett Peters.  All rights reserved, no warranty. Use at own risk.