compress.sh

#!/bin/bash

# Recursive File Compression Script
# Author: V. Alex Brennen <vab@mit.edu>
# License: This script is public domain
# Date: 2014-03-17

# Description: This script will take a directory as an argument.
# It will then transverse the directory, and all sub directories,
# and compress the regular files in those directories with bzip2.
# The script just ignores any files that are not either a regular
# file or a directory (symbolic links, devices, etc).

BZIP2=/bin/bzip2
NICE=/bin/nice

# Compression level
CLVL="-9"

# Use nice
BE_NICE=1

# Nice level
NLVL=19

# Test for a server list file argument
if [ -z "$1" ]; then
echo "Usage: $0 <directory>";
exit
fi

# Make sure the directory is valid and readable
if [ ! -d "$1" ]; then
echo "Error: Argument does not appear to be a directory: $1."
exit
fi

# This is the function that does the actual compression and 
# directory transversal.
function compress_files
{
	for i in $( ls );
	do
		if [ -f $i ]; then
		    if [ $BE_NICE -eq 1 ]; then
		    	$NICE -$NLVL $BZIP2 $CLVL $i
		    else
			    $BZIP2 $CLVL $i
			fi
		elif [ -d $i ]; then
			cd $i
			compress_files
			cd ..
		fi
	done
}

# To start the script, we change the current working directory
# to the directory to compress then kick off the initial call 
# to the recursive compress_files function.
cd $1
compress_files