p7zip VS precomp-cpp

nearly every main distro I am aware of has both available. The reason you still see p7zip is because the CLI incompatibilities vs the newer 7z/7zip executables and the general licensing issues. Most users of "old p7zip" are actually using the actively maintained https://github.com/p7zip-project/p7zip which is updated, supporting unix permissions and zstd and so on.

Thank you for pointing this out! This is the source of much confusion. Although Arch for example uses https://github.com/jinfeihan57/p7zip which seems to be reasonably maintained?

Then you can compile p7zip from source: $ mkdir p7zip-git $ cd p7zip-git $ git clone https://github.com/jinfeihan57/p7zip .

April 4th was the latest release. Had some commits in May. I think it is active.

I think the point is, the '7z' at 17.04 available in Arch Linux's repo is actually p7zip, the development of which is independent of 7-zip. So comparison of the version number is meaningless (if I am right). Also, p7zip 17.04 is released in April this year, not 2017, according to its release page

this comment might clarify that.

You should look at Precomp - an apparently abandoned, but awesomely working arhiver that is dedicated to compressing those ZIP-based formats, and compresses them twice-thrice as small as LZMA2 can.

You can also have a look at this packer. It compresses PDF and EPUB 2-3 times smaller than 7z at maximum settings, at half the speed. I keep all my books in it and never had a problem.

There is an opensource archiver called precomp that is designed specifically for e-documents and compresses them 2-3 times smaller than 7z in ultra mode. It works, and I keep my e-books in it. However, it seems nobody else does, and development has stopped due to lack of interest.

There are tools like preflate [1] or precomp [2] that guarantees a bitwise identical reconstruction, of course modulo bugs.

[1] https://github.com/deus-libri/preflate

[2] https://github.com/schnaader/precomp-cpp/ (which internally makes use of preflate)

You may use "precomp" in order to seek and uncompress those parts. Then you can use a better compression algorithm : http://schnaader.info/precomp.php

Precomp http://schnaader.info/precomp.php is a program which will seek compressed parts and decompress those parts in order to compress with another algorithm. This greatly improve compression ratio with the other algorithm.

This may be of help. (a255854 and d649919)