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<article>

<title>Saving Space mini-HOWTO 

<author>By Guido Gonzato, <url url="mailto:guido@ibogeo.df.unibo.it">

<date>v1.0.1, 7 April 1999

<abstract>

This mini-HOWTO gives you directions for squeezing your Linux installation
into the least possible space. It's particularly aimed at notebook users.

</abstract>

<toc>


<sect> Introduction

<p>

I've got a notebook I installed Linux on, beside Windows 95 that was
pre--installed. I squeezed the Windows partition to 500 Mb, making space for
a 240 Mb Linux one. Small though the latter may seem, I've managed to
install a fairly complete Linux system on it, based on Red Hat 4.1 and some
magic to save as much space as possible.

If you're in need for space, the indications you'll find in the following
sections will free up a considerable chunk of hard disk. The only caveat I'm
giving you is: don't blame me if something goes wrong! We'll be using a
couple of programs that worked fine for me, but are inherently dangerous.
You've been warned.


<sect> Software requirements

<p>

You need:

<itemize>

<item> a fully working Linux system (any version should be OK);

<item> the common <tt/gzip/ compression utility, or alternatively <tt/bzip2/
that you find on
<url url="ftp://sunsite.unc.edu:/pub/Linux/utils/compress">; 
this tool compresses better than <tt/gzip/, but it's also a wee bit slower 
and consumes a lot of memory;

<item> the <tt/upx/ executable compressor, whose home page is at
<url url="http://cdata.tvnet.hu/~ml/upx.html"> and 
<url url="http://wildsau.idv.uni-linz.ac.at/mfx/upx.html">;

<item> the <tt/zlibc/ package, available on <url
url="ftp://sunsite.unc.edu:/pub/Linux/libs/compression">. It's 
called <tt/zlibc-X.X.tar.gz/, where <tt/X.X/ is the latest version.

</itemize>

There are other executable compressors. One is <tt/gzexe/ (forget it), while
<tt/tcx/ was probably the best before <tt/upx/ became available; yet another
is <tt/tzx/, in theory better than <tt/tcx/. The thing is, it screwed
everything up when I tried it on a spare PC, though I'm not sure if I did
something wrong. You had better stick with <tt/upx/: it's reliable,
efficient, and very handy.

There are kernel patches that provide transparent file system compression a
la Stacker, but as of this writing none of them has yet a reputation for
stability and reliability. For safety's sake, steer clear.


<sect> The procedure

<p>


<sect1> Removing the Kernel Sources

<p>

The kernel sources take up more than 20 Mb, and you may want to remove them.
If so, I suggest that you compile a new kernel that is tailored to your
machine once and for all, then get rid of the sources. Take care, though.

I <em/don't/ recommend that you remove the kernel sources unless you are
sure that your machine is properly configured. Besides, you need the kernel
&num;includes to compile C programs. Think twice!

If you do decide so, <em/do not/ remove the <file>include/linux</file> tree
unless you know you'll never compile applications on your machine.


<sect1> Pruning Out Applications

<p>

Now, decide which applications you <em/really/ need. Some may prove
redundant: for instance, are you sure you can't live without <tt/emacs/? You
could use <tt/jed/ instead.

It's up to you to decide what you want to keep. Some general points:

<itemize>

<item> <tt/gcc/ is a fairly large package. It's needed to recompile the
kernel and all the applications for which there are no pre--built Linux
binaries. It's also needed, of course, if you write your own C or Fortran
(with <tt/f2c/ or <tt/g77/) programs; consider your needs before removing it.
Other compilers like <tt/lcc/ are fine, but not up to <tt/gcc/ level. I
suggest that you keep it;

<item> X11 is awfully large, but it's a nice thing to have. If you decide
you can't give it up, at least try to make do with as little as necessary:
only the right X server, one simple window manager, only one
<tt/xterm/, no 100 dpi fonts, and so on;

<item> TeX and accompanying packages are very large indeed. Giving up LaTeX
and sticking to plain TeX saves a lot of space; giving up X11 previewers
like <tt/xdvi/ and <tt/ghostview/ is possible if you use <tt/dvitty/,
<tt/dvivga/ and some such. Eliminating the need for X11 dviware could even
make X11 redundant;

<item> games are never ``necessary''.

</itemize>


<sect1> Stripping Binaries

<p>

Let's start reducing the size of binaries. Move to <file>/usr/bin</file> and
issue the command

<tscreen><verb>
machine:/usr/bin# strip *
</verb></tscreen>

which will do away with symbols embedded in binaries. Repeat this
step in <file>/usr/X11R6/bin/</file> and other directories containing
executables you may have (don't forget to locate TeX's and <tt/gcc/'s 
binaries), but <em/do not/ run it under <file>/sbin</file>, 
<file>/bin</file>, or <file>/usr/sbin/</file> if you value your installation!


<sect1> Compressing with <tt/upx/

<p>

First, install <tt/upx/ and read its documentation. Then go to
<file>/usr/bin</file> and run it with the command <tt>upx *</tt>; it will
compress all executables, including suid ones (<tt/tcx/ wouldn't). Repeat
this step in other directories as seen above.

Remember to compress the executables whenever you install a new package!


<sect1> Gzipping around

<p>

There are lots of other files that can be compressed once and for all. Let's
start with <file>/usr/doc/</file>; move to this directory and issue the 
command

<tscreen><verb>
machine:/usr/doc# find . -type f -exec gzip -9 {} \; 2> /dev/null
</verb></tscreen>

Remember to compress the docs whenever you install a new package!

Repeat this step in the directory containing the documentation for TeX (on
my system, <file>/usr/lib/texmf/texmf/doc/</file>. If you're 
<em/really sure/, remove these directories altogether.

Now, install <tt/zlibc/ and compile it. If your system is like mine, the
compilation process will abort complaining about a missing (static) libc.
Never mind; you'll find a file called <tt/uncompress.o/ that is what's
needed. Move it to <file>/usr/local/lib/</file> and add this line to your
<file>/etc/profile</file>:

<tscreen><verb>
export LD_ELF_PRELOAD=/usr/local/lib/uncompress.o
</verb></tscreen>

Now, you can compress with <tt/gzip/ not only documentation, but also data
files: the applications that use them will be able to use them nonetheless.
In theory, the trick should work with most applications, but in practice
your degree of success may vary. Mine was rather unimpressive.


<sect> A Real Life Example

<p>

This is what I got applying the above procedure to one of my machines.
Before the treatment, <tt/df/ reported I used 398,798 1024--blocks:

<itemize>

<item> I didn't remove the kernel sources and the kernel headers;

<item> I uninstalled several applications and all of the games, but I left
X11, X11 development, C and Fortran development, Tcl/Tk, networking tools, 
and a few other standard applications. <tt/df/ reported 244,668 used blocks;

<item> I ran <tt/upx/ on <file>/usr/bin</file>, 
<file>/usr/X11R6/bin</file>, <file>/usr/lib/texmf/bin/i586-linux</file>, 
and <file>/usr/lib/gcc-lib/i386-linux/2.7.2.1</file>. 226,270 used blocks;

<item> I compressed the documentation under <file>/usr/doc</file> and
<file>/usr/lib/texmf/texmf/doc</file>: 198,745 used blocks.

</itemize>

To sum up, I started with 398,798 blocks and finished with 198,745. Think of
the stuff you can shove in those 200,000 spared blocks! I would have saved
even more if I had used <tt/bzip2/ instead of <tt/gzip/.

On average, if you are careful from the beginning and install only the
necessary applications, compressing executables and documents will save you
some 20 Mb. On a notebook, this can be a lifesaver.


<sect> The End

<p>

<sect1> Copyright

<p>

Unless otherwise stated, Linux HOWTO documents are copyrighted by their
respective authors. Linux HOWTO documents may be reproduced and distributed
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All translations, derivative works, or aggregate works incorporating any
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In short, we wish to promote dissemination of this information through as
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If you have questions, please contact Tim Bynum, the Linux HOWTO
coordinator, at tjbinum@sunsite.unc.edu via email.

<sect1> Disclaimer

<p>

``Saving Space mini-HOWTO''was written by Guido Gonzato,
<url url="REMOVE_MEguido@ibogeo.df.unibo.it">.

This document is provided ``as is''. I put great effort into writing it as
accurately as I could, but you use the information contained in it at your
own risk. In no event shall I be liable for any damages resulting from the
use of this work.

Feedback is welcome. For any requests, suggestions, flames, etc., feel free
to contact me.

Enjoy Linux and life,

Guido   <tt/=8-)/

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