Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

File compression works on the basic idea of assigning commonly recurring chains of strings to a common index of a table where the full string is stored.

For example:

Input file: foo bar bash baz foo foo bash foo baz baz foo baz foo bar
Output file: foo ,bar ,bash ,baz |01230020330301

I understand that this is a trivial example and actual file structures and algorithms are much more complex, but my question is, are there any existing compression utilities that provide options for viewing this sort meta-data in some way given a specific archive? Possibly for educational purposes?

share|improve this question
I'm not sure this is always possible. From what I understand, in a file compressed using an adaptive Huffman coding, the “metadata” depends on the data itself, and the table you describe actually evolves during the extraction of the file. – Vincent Nivoliers Nov 14 '12 at 23:00
I wonder if possibly there is a compression utility that uses a simpler algorithm useable for education purposes. – Cory Klein Nov 14 '12 at 23:05
@CoryKlein Grab sources of some compression utility (gzip, xz...), add debug code, that will print the dictionary and run it on a simple file you prepare. That's one of the original reasons behind GPL - being able to study and modify the code that is running on your system. :) – peterph Nov 15 '12 at 10:09

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.