#!/bin/sh -u
# unpack some tar archives containing image fragments and assemble a JPEG image
# -----
# Syntax:    $0
# -----
# Purpose:
#  (Sample solution to Exercise #3)
#  Examine a tar archive and locate 2,725 image fragment files hidden
#  in various places.  Assemble the image fragments into a JPEG image.
#  Issue status reports at each step of the process, showing that we
#  have the correct files available at each step.
# -----
# Student Name:                 Ben Dover
# Algonquin EMail Address:      abcd0001
# Student Number:               074-210-779 
# Course Number:                DAT2330  
# Lab Section Number:           014 
# Professor Name:               Ian Allen 
# Assignment Name/Number/Date:  Exercise #3 due March 9, 2004
# Comment:                      number one of two files
# -----
# -IAN! idallen@idallen.ca

# Use a standard search path and friendly umask for the commands in this script.
#
PATH=/bin:/usr/bin
export PATH
umask 022

# Set the name of the temporary directory we will use;
# this directory will be removed at the end of the script.
#
tmpdir=tmpdir

# Silently remove any previous existing "$tmpdir".
# Create a new temporary directory and make it the current directory.
# Show the current directory.
#
echo "--- Part (a) ---"
rm -rf "$tmpdir"
mkdir "$tmpdir" || exit 1
cd "$tmpdir" || exit 1
pwd

# Link the hidden tar file from the instructor to the current directory.
# I know that this is a compressed tar archive, so I name it "my.tar.gz".
# Expand the tar file and remove (unlink) it.
# Show a count of files in the current directory.
#
echo "--- Part (b) ---"
ln ~idallen/public_html/teaching/dat2330/04w/notes/.exercise03 my.tar.gz \
	|| exit 1
tar xzf my.tar.gz || exit 1
rm my.tar.gz
ls -a | wc

# We already determined which of the contained files were tar files.
# Do a verbose count of their contents.
#
echo "--- Part (c) ---"
tar  tvf part1 | wc
tar  tvf part2 | wc
tar tzvf part3 | wc

# Expand these tar files and delete them.
# Run a word count on the directory to show how many files it contains.
# Run a second count to show how many pathnames are under this directory.
#
echo "--- Part (d) ---"
tar  xf part1 || exit 1
tar  xf part2 || exit 1
tar xzf part3 || exit 1
rm part[123]
ls -a | wc 
find | wc

# Count pathnames containing "/x".
# Count pathnames containing "/x" and containing "part1".
# Count pathnames containing "/x" and NOT containing "part1".
#
echo "--- Part (e) ---"
find | grep "/x" | wc
find | grep "/x" | grep    "part1" | wc
find | grep "/x" | grep -v "part1" | wc

# Go to the directory containing compressed files and uncompress them.
# Show a file count and name checksum on each of the two directories.
#
echo "--- Part (f) ---"

cd ".part 2/.Part 2/. Part2"
gunzip *.gz || exit 1
ls | wc
ls | sum
cd ../../.. || exit 1

cd ".part1/.parT1/.paRt1" || exit 1
ls | wc
ls | sum
cd ../../.. || exit 1

# We already determined where the "mystery" file was.
# We examined it and found that it was a compressed tar archive full
# of bzip2 compressed image fragments.  Make a new temp directory and
# expand the archive there, then uncompress the fragments.
# Show a file count and name checksum on the directory.
#
echo "--- Part (g) ---"
mkdir p3 || exit 1
cd p3 || exit 1
tar xzf "../.?????/.*****/.[][][]/mystery" || exit 1
bunzip2 *.bz2 || exit 1
ls | wc
ls | sum
cd .. || exit 1

# Set the name of the output file for the image.
# Create the image from the pieces.
# Show some stats on the image.
# Move the image up to the parent directory (where we started).
# Move to the parent.
# Delete the entire temp directory used to create the image.
#
echo "--- Part (h) ---"
tuxfile=tux-kong.jpg
cat ".part1/.parT1/.paRt1"/* ".part 2/.Part 2/. Part2"/* p3/* >"$tuxfile" \
	|| exit 1
wc "$tuxfile"
sum "$tuxfile"
mv "$tuxfile" .. || exit 1
cd .. || exit 1
rm -r "$tmpdir"

# The script exits with the return status of the last command executed.