Autoztool contains a command called z, which executes the command found on its command line, in an environment in which compressed files are automatically and mostly transparently decompressed when they are opened for reading.

You use this command much like nohup or nice. For example:

z less truss-geneaology.text.gz

Especially if you have zless already this example probably doesn’t seem very compelling. The advantages appear if you don’t have a “z” variant of a command, or where the behaviour of the “z” version differs in some unhelpful or ugly way from the standard version.

For example, on my system, running zless with multiple filenames on the command line produces much less user-friendly behaviour than standard less, and using “z less” instead solves this.

Supported Systems

Platform Notes
Debian Should work without difficulty. See below for deb files.
Other Linux Should work but not tested. Build from source.
OS X Mostly works. The limitation is that it forces a flat namespace at link time, so anything that actually depends on two-level namespace lookups won’t work properly.

It could at least in theory be ported to other systems which have LD_PRELOAD or something sufficiently similar. If you do such a port, please send me a patch. (Use “diff -u”.)


File Contents
autoztool_0.3_i386.deb .deb for 32-bit Debian systems
autoztool_0.3_amd64.deb .deb for 64-bit Debian systems
autoztool-0.3.tar.gz Source code git clone git://


Please report bugs to me at You should check that your bug is not fixed in a later version before doing so.


If you think this sounds like zlibc then you wouldn’t be far wrong. However Autoztool is smaller and simpler, and intended to provide convenient access to occasional compressed files, rather than to do the whole job of emulating a compressed filesystem.


Copyright © 2001, 2003, 2010, 2011 Richard Kettlewell.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

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