Easily inject files into jpeg files (using the comment tag in the EXIF data)

jpeginjector.sh

#!/bin/bash

# jpegincector.sh - Easily inject files into jpeg files (using the comment tag in the EXIF data)
# You need this tools / programs to run jpeginjector.sh:
# * uuencode/uudecode (usually found in the sharutils package)
# * exiftool (usually found in the perl-Image-ExifTool package)
# * uuidgen (usually already installed)
#
#            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
#                    Version 2, December 2004
# 
# Copyright (C) 2004 Sam Hocevar
#  14 rue de Plaisance, 75014 Paris, France
# Everyone is permitted to copy and distribute verbatim or modified
# copies of this license document, and changing it is allowed as long
# as the name is changed.
# 
#            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
#   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
# 
#  0. You just DO WHAT THE FUCK YOU WANT TO.

do_inject() {
	TEMP_UUE_FILE="/tmp/$(uuidgen)"
	uuencode -m `basename "$1"` < "$1" > "$TEMP_UUE_FILE"
	exiftool -Comment"<=$TEMP_UUE_FILE" "$2"
	rm -f "$TEMP_UUE_FILE"
}

do_extract() {
	TEMP_UUE_FILE="/tmp/$(uuidgen)"
	if ! exiftool -b -Comment $1 > "$TEMP_UUE_FILE" 2> /dev/null; then
		echo "Could not extract file. Perhaps no valid JPEG file?" >&2
		rm "$TEMP_UUE_FILE"
		return 1
	fi
	
	uudecode "$TEMP_UUE_FILE"
	RETVAL=$?
	rm -f "$TEMP_UUE_FILE"
	return $RETVAL
}

PRGNAME=`basename "$0"`

case "$1" in
	inject)
		if [ $# -ne 3 ]; then
			echo -e "$PRGNAME: Command \"$1\" needs two parameters.\n$PRGNAME help for more information." >&2
			exit 1
		else
			do_inject "$2" "$3"
		fi
		;;
	extract)
		if [ $# -eq 2 ]; then
			do_extract "$2"
		else
			echo -e "$PRGNAME: Command \"$1\" needs one parameter.\n$PRGNAME help for more information." >&2
		fi
		;;
	help)
		cat <<-HELPTEXT
			Usage: $PRGNAME COMMAND FILE1 [FILE2]
			Where COMMAND is one of these:
			
			help
			Print this help.
			
			inject FILE JPEG
			Injects FILE into JPEG.
			
			extract JPEG
			Extracts a file from JPEG.
		HELPTEXT
		;;
	*)
		if [ "$1" == "" ]; then
			echo -e "$PRGNAME: No command given.\nUsage: $PRGNAME COMMAND [FILE1] [FILE2]\n\"$PRGNAME help\" for more information." >&2
			exit 1
		else
			echo -e "$PRGNAME: Unknown command: \"$1\".\nUsage: $PRGNAME COMMAND [FILE1] [FILE2]\n\"$PRGNAME help\" for more information." >&2
		fi
esac