Zutils is a collection of utilities able to deal with any combination of
compressed and uncompressed files transparently. If any given file,
including standard input, is compressed, its decompressed content is
used. Compressed files are decompressed on the fly; no temporary files
These utilities are not wrapper scripts but safer and more efficient C++
programs. In particular the "--recursive" option is very efficient in
those utilities supporting it.
The provided utilities are:
zcat - Decompresses and copies files to standard output.
zcmp - Decompresses and compares two files byte by byte.
zdiff - Decompresses and compares two files line by line.
zgrep - Decompresses and searches files for a regular expression.
ztest - Tests integrity of compressed files.
zupdate - Recompresses files to lzip format.
The supported formats are bzip2, gzip,
lzip and xz.
The compressor to be used for each format is configurable at runtime.
zcat, zcmp, zdiff, and zgrep are improved replacements for the shell
scripts provided by GNU gzip. ztest is unique to zutils. zupdate is
similar to gzip's znew.
NOTE: Bzip2 and lzip provide well-defined values of exit status, which
makes them safe to use with zutils. Gzip and xz may return ambiguous
warning values, making them
less reliable back ends for zutils.
LANGUAGE NOTE: Uncompressed = not compressed = plain data; it may never
have been compressed. Decompressed is used to refer to data which has
undergone the process of decompression.
The manual is available in the info system of the GNU
Operating System. Use info to access the top level info
page. Use info zutils to access the zutils section directly.
An online manual for zutils can be found
The latest released version of zutils can be found
You may also subscribe to
and receive an email every time a new version is released.
How to Get Help
For general discussion of bugs in zutils the mailing list
is the most appropriate forum. Please send messages as plain text.
Please do not send messages encoded as HTML nor encoded as base64 MIME
nor included as multiple formats. Please include a descriptive subject
line. If all of the subject are "bug in zutils" it is impossible to
An archive of the bug report mailing list is available at
How to Help
To contact the author, either to report a bug or to contribute fixes or
improvements, send mail to
Please send messages as plain text. If posting patches they should be in
unified diff format against the latest version. They should include a
See also the
project page at Savannah.
These programs are free software: you can redistribute them and/or
modify them under the terms of the
GNU General Public
License as published by the Free Software Foundation, either version
3 of the License, or (at your option) any later version.
Copyright © 2014 Antonio Diaz Diaz
You are free to copy, modify and distribute all or part of this article