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.
FORMAT NOTE: If the "--format" option is given, the corresponding files are passed to the decompressor without verifying their format, allowing for example the processing of compress'd (.Z) files with gzip: "zcmp --format=gz file.Z file.lz".
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.
An online manual for zutils can be found here.
An archive of the bug report mailing list is available at http://lists.nongnu.org/mailman/listinfo/zutils-bug.
See also the zutils project page at Savannah.
You are free to copy, modify and distribute all or part of this article without limitation.