Edit uncompress/zlib with gzip data cheat sheet

Title:

Last edited: 12:14:26 pm on 22 June 2021 by 3.0.1.3

From *https://newbedev.com/how-to-uncompress-zlib-data-in-unix*:

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! How to uncompress zlib data in UNIX?

<b>Solution:</b>

It is also possible to decompress it using standard shell-script + gzip, if you don't have, or want to use openssl or other tools.
The trick is to prepend the gzip magic number and compress method to the actual data from zlib.compress:

<code>
printf "\x1f\x8b\x08\x00\x00\x00\x00\x00" |cat - /tmp/data |gzip -dc >/tmp/out
</code>

Edits:
<blockquote>
 @d0sboots commented: For RAW Deflate data, you need to add 2 more null bytes:
<code>
"\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x00"
</code>
</blockquote>

This Q on SO gives more information about this approach. An answer there suggests that there is also an 8 byte footer.

Users @Vitali-Kushner and @mark-bessey reported success even with truncated files, so a gzip footer does not seem strictly required.

@tobias-kienzler suggested this function for the bashrc:
<code>
zlipd() (printf "\x1f\x8b\x08\x00\x00\x00\x00\x00" |cat - $@ |gzip -dc)

zlib-flate -uncompress < IN_FILE > OUT_FILE
</code>

I tried this and it worked for me.

zlib-flate can be found in package qpdf (in Debian Squeeze and Fedora 23, according to comments in other answers)

(Thanks to user @tino who provided this as a comment below the OpenSSL answer. Made into propper answer for easy access.)

I have found a solution (one of the possible ones), it's using openssl:

<code>
$ openssl zlib -d < /tmp/data
</code>

<code>
$ openssl zlib -d -in /tmp/data
</code>

&star;NOTE: zlib functionality is apparently available in recent openssl versions >=1.0.0 (OpenSSL has to be configured/built with zlib or zlib-dynamic option, the latter is default)

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