Glitching scripts

all_bytes.sh

#!/bin/sh

# author: tsulej 2015 // glitching tools
# e-mail: [email protected]
# Script traverse through the file changes one byte and saves result. Outcome: files with changed first, second, third, ..., nth byte to choosen value
# usage:
#  bash ./all_bytes.sh <filename.ext> <hex value, two letters: 0..f>
#  warning: use files with small size (<20kb)
# example, suppose we have image.gif file with size 999 bytes:
#  bash ./all_bytes.sh image.gif aa
#  result is 999 files: 001_image.gif (first byte set to 'aa'), 002_image.gif (second byte set to 'aa'), ..., 999_image.gif (999th byte set to 'aa')

# dependencies: sed, xxd, change_byte.sh
# can be used under linux or cygwin

size=`stat -c '%s' "$1"`
name=`echo "$1" | cut -d '.' -f 1`
ext=`echo "$1" | cut -d '.' -f 2`

for i in `seq -w 1 $size`
do
  echo "Processing byte $i"  
  bash ./change_byte.sh "$1" $i $2
  mv "$name".res.$ext "$i"_"$name".$ext
done

change_byte.sh

#!/bin/sh

# author: tsulej 2015 // glitching tools
# e-mail: [email protected]
# bash script which changes choosen byte in the binary file to a value
# usage:
#   bash ./change_byte.sh <filename.ext> <byte number> <hex value, two letters: 0..f>
#   result is saved in the file "filename.res.ext"
# example, change 1000th byte to '9d' value:
#   bash ./change_byte.sh image.jpg 1000 9d
#   result save to image.res.jpg

# dependencies: sed, xxd
# can be used under linux or cygwin

echo -n "file $1... "

# $1 - filename to process
# get name and extention
name=`echo "$1" | cut -d '.' -f 1`
ext=`echo "$1" | cut -d '.' -f 2`

# produce pure hex, each byte in other line
# save it in the /name/.hex file
xxd -ps -c 1 < "$1" > "$name".hex

# replace bytes in line $2 with byte from $3
sed -s "$2 s/^../$3/" < "$name".hex > "$name".2.hex

# save to binary back
xxd -r -ps -c 1 < "$name".2.hex > "$name".res.$ext

# remove all tmp files
rm "$name".hex
rm "$name".2.hex

echo "processed";

process_files.sh

#!/bin/sh

# author: tsulej 2015 // glitching tools
# e-mail: [email protected]
# bash script for batch byte change (see change_byte.sh)
# usage:
#   bash ./process_files.sh <ext - file extension> <byte number> <hex value, two letters: 0..f>
# example, change 1000th byte to 'f3' value in all png files in directory:
#   bash ./process_files.sh png 1000 f3
#
# dependencies: sed, xxd, change_byte.sh
# can be used under linux or cygwin

for i in *.$1
do
  echo "Processing file: $i"  
  bash ./change_byte.sh "$i" $2 $3  
done