Simple command line parser in Bash

I wanted to create a simple yet flexible way to parse command line arguments in bash. I used case statement, and some expression expansion technique to read arguments in a simple manner. I find this very handy, and hoping you will find it useful in solving or simplifying your task as well. Whether it is a serious script or a quick hack, clean programming makes your script more efficient and also easier to understand.

usage() {
echo -e "No command-line argument\n"
echo "Usage: $0 "
echo "Arguments:"
echo -e " --copy-from-hdfs\tcopy data set resides in HDFS"
echo -e " --copy-to-s3\t\tcopy files to S3 in AWS"
echo -e " --gzip\t\t\tcompress source files, recommended before sending data set to S3"
echo -e " --remote-dir=\t\tpath to input directory (HDFS directory)"
echo -e " --local-dir=\t\tlocal tmp directory (local directory)"
echo -e " --s3-bucket-dir=\ts3 bucket directory in AWS"
exit 1
}

# Check command line args
if [ -z $1 ]
then
usage
else
# Parsing commandline args
for i in $*
do
case $i in
-r=*|--remote-dir=*)
#DM_DATA_DIR=`echo $i | sed 's/[-a-zA-Z0-9]*=//'` -- > this work but using expression expansion below is a much nicer and compact way
DM_DATA_DIR=${i#*=}
;;
-l=*|--local-dir=*)
AMAZON_DATA_DIR=${i#*=}
;;
-s3=*|--s3-bucket-dir=*)
#S3_DIR=`echo $i | sed 's/[-a-zA-Z0-9]*=//'`
S3_DIR=${i#*=}
;;
--copy-from-hdfs)
COPY_FROM_HDFS=YES
;;
--copy-to-s3)
COPY_TO_S3=YES
;;
-c|--gzip)
COMPRESS=YES
;;
*)
# Unknown option
;;
esac
done

Thoughts, and suggestions are welcome!