Change file extensions in a directory.

rename.sh

#!/bin/bash
<<COMMENT
Author: Samuel Huang
rename.sh: change file extensions in a directory
COMMENT

path="."
interact=false
recurse=false

if [ $# -eq 0 ] ; then
	echo "Usage: $0 [OPTION]... [OLD] [NEW]"
	echo "Try $0 -h for more information."
	exit 1
fi

function usage() {
cat <<EOF
Usage: $0 [OPTION]... [OLD] [NEW]
    -h: help
    -i: interactive
    -p: desired path
    -r: recursive
EOF
}

# reading optional parameters
while getopts :hip:r opt ; do
	case $opt in
		h)
			usage
			exit 0
			;;
		i)
			interact=true
			read -p "Enter old extension: " OLD
			read -p "Enter new extension: " NEW
			read -p "Enter desired path: " path
			read -p "Recursive (Y/N): " var
			if [ "$var" == "Y" ] ; then
				recurse=true
			fi
			;;
		p)
			path="$OPTARG"
			;;
		r)
			recurse=true
			;;
		\?)
			echo "Invalid option: -$OPTARG"
			;;
		:)
			echo "Option -$OPTARG requires an argument."
			exit 1
			;;
	esac
done

# remove optional parameters
shift $(($OPTIND - 1))

if ! $interact ; then
	OLD="$1"
	NEW="$2"
fi

if $recurse ; then
	fls=`/bin/find $path -type f -name "*.$OLD"`
else
	fls=`/bin/ls $path/*.$OLD`
fi

# heavy-lifting
for ofile in $fls ; do
	nfile=${ofile%.$OLD}.$NEW
	/bin/mv $ofile $nfile
done