rename_images

#!/bin/bash

for FILENAME in "$@"
do
	export FILENAME
	NEWNAME="$(exiv2 $FILENAME | grep "Image timestamp" | cut -d ' ' -f 4,5 | sed 's/\(.*\) \(.*\)/\1T\2.jpg/')"

	# don't forget to quote
	if [ "$NEWNAME" != "" ] # equivalent to [ -n "$NEWNAME" ]
	then
		mv "$FILENAME" "$NEWNAME"
	elif [ ! -e "$FILENAME" ] # file does not exist
	then
		echo "$0: $FILENAME: No such file" 1>&2
	else
		echo "$0: $FILENAME: No EXIF timestamp" 1>&2
	fi
done

rename_images_getopts

#!/bin/bash

while getopts "e:" opt "$@"
do
	case $opt in 
		e)
			export EXTENSION="$OPTARG"
			;;
		\?)
			echo "Invalid option: -$OPTARG" >&2
			;;
	esac
done

for FILENAME in "${@:$OPTIND}"
do
	export FILENAME
	# this line is changed
	NEWNAME="$(exiv2 $FILENAME | grep "Image timestamp" | cut -d ' ' -f 4,5 | sed 's/\(.*\) \(.*\)/\1T\2'"$EXTENSION"'/')"

	# don't forget to quote
	if [ "$NEWNAME" != "" ] # equivalent to [ -n "$NEWNAME" ]
	then
		mv "$FILENAME" "$NEWNAME"
	elif [ ! -e "$FILENAME" ] # file does not exist
	then
		echo "$0: $FILENAME: No such file" >&2
	else
		echo "$0: $FILENAME: No EXIF timestamp" >&2
	fi
done