DEX files are embeded in Android ART .oat/.odex files. oat2dexes looks for
DEX magic "dex\n035\0".
$ file file.odex
file.odex: ELF 32-bit LSB shared object, ARM, version 1 (GNU/Linux), dynamically linked, stripped
$ gcc -o oat2dexes -Wall oat2dexes.c
$ ./oat2dexes file.odex
Writing 12345 bytes to dex01.dex
$ java -jar baksmali.jar -o outdir dex01.dex
(last step not really important just in case if you obtain an working dex for decompile)
You can also use the build.sh script for build an binary :D
This project is a fork from: https://github.com/wuyongzheng/oat2dexes
Using zero skill and experience on the C language i implemented some stuff to detect dex files with the same name and increment it's number value for avoid overwriting, i tested it only on Linux so therefore i don't guarantee that this will work on Windows as well.