Entropy Analyzer Tool is a simple shell script that analyzes file entropy by compressing it using gzip or bzip2 compression algorithms and shows the file size percentage after compression from original file size.

This might be very useful when reverse-engineering some unknown binary files to get a basic understanding of its internal structure and answer some of the questions, like "is it encrypted?" or "is it compressed?".

For example, if you have file some_document.txt which shows 16% - this means that the size of some_document.txt after compression is only 16% from original file size.

Basically, if file can't be compressed much - it has a high entropy and if the compressed size is much smaller than the original - the entropy is pretty low.

Before running this tool, you need to have gzip and bzip2 archivers installed on your system (usually those two are installed on most Linux distibutions and most Unix'es)

To see all available options, run:

$ ./eat.sh --help

and to analyze some files, pass the script some file path(s):

$ ./eat.sh some_file.bin some_other_file.dat
97% some_file.bin
23% some_other_file.dat