en/handbook/hb-working-features.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE sections SYSTEM "/dtd/book.dtd">

<!-- The content of this document is licensed under the CC-BY-SA license -->
<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->

<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-working-features.xml,v 1.41 2012/03/28 22:44:07 nightmorph Exp $ -->

<sections>

<abstract>
Discover the features Portage has, such as support for distributed compiling,
ccache and more.
</abstract>

<version>6</version>
<date>2012-06-29</date>

<section>
<title>Portage Features</title>
<body>

<p>
Portage has several additional features that makes your Gentoo experience even
better. Many of these features rely on certain software tools that improve
performance, reliability, security, ...
</p>

<p>
To enable or disable certain Portage features you need to edit
<path>/etc/make.conf</path>'s <c>FEATURES</c> variable which contains the
various feature keywords, separated by white space. In several cases you
will also need to install the additional tool on which the feature relies.
</p>

<p>
Not all features that Portage supports are listed here. For a full overview,
please consult the <path>make.conf</path> man page:
</p>

<pre caption="Consulting the make.conf man page">
$ <i>man make.conf</i>
</pre>

<p>
To find out what FEATURES are default set, run <c>emerge --info</c> and search
for the FEATURES variable or grep it out:
</p>

<pre caption="Finding out the FEATURES that are already set">
$ <i>emerge --info | grep FEATURES</i>
</pre>

</body>
</section>
<section>
<title>Distributed Compiling</title>
<subsection>
<title>Using distcc</title>
<body>

<p>
<c>distcc</c> is a program to distribute compilations across several, not
necessarily identical, machines on a network. The <c>distcc</c> client sends all
necessary information to the available distcc servers (running <c>distccd</c>) 
so they can compile pieces of source code for the client. The net result is a 
faster compilation time.
</p>

<p>
You can find more information about <c>distcc</c> (and how to have it work 
with Gentoo) in our <uri link="/doc/en/distcc.xml">Gentoo Distcc
Documentation</uri>.
</p>

</body>
</subsection>
<subsection>
<title>Installing distcc</title>
<body>

<p>
Distcc ships with a graphical monitor to monitor tasks that your computer is
sending away for compilation. If you use Gnome then put 'gnome' in your USE
variable. However, if you don't use Gnome and would still like to have the
monitor then you should put 'gtk' in your USE variable.
</p>

<pre caption="Installing distcc">
# <i>emerge distcc</i>
</pre>

</body>
</subsection>
<subsection>
<title>Activating Portage Support</title>
<body>

<p>
Add <c>distcc</c> to the FEATURES variable inside <path>/etc/make.conf</path>.
Next, edit the MAKEOPTS variable to your liking. A known guideline is to fill in
"-jX" with X the number of CPUs that run <c>distccd</c> (including the current
host) plus one, but you might have better results with other numbers.
</p>

<p>
Now run <c>distcc-config</c> and enter the list of available distcc servers. For
a simple example we assume that the available DistCC servers are 192.168.1.102
(the current host), 192.168.1.103 and 192.168.1.104 (two "remote" hosts):
</p>

<pre caption="Configuring distcc to use three available distcc servers">
# <i>distcc-config --set-hosts "192.168.1.102 192.168.1.103 192.168.1.104"</i>
</pre>

<p>
Don't forget to run the <c>distccd</c> daemon as well:
</p>

<pre caption="Starting the distccd daemons">
# <i>rc-update add distccd default</i>
# <i>/etc/init.d/distccd start</i>
</pre>

</body>
</subsection>
</section>
<section>
<title>Caching Compilation</title>
<subsection>
<title>About ccache</title>
<body>

<p>
<c>ccache</c> is a fast compiler cache. When you compile a program, it will
cache intermediate results so that, whenever you recompile the same program, the
compilation time is greatly reduced. The first time you run ccache, it will be
much slower than a normal compilation. Subsequent recompiles should be faster.
ccache is only helpful if you will be recompiling the same application many
times; thus it's mostly only useful for software developers.
</p>

<p>
If you are interested in the ins and outs of ccache, please visit the 
<uri link="http://ccache.samba.org">ccache homepage</uri>.
</p>

<warn>
<c>ccache</c> is known to cause numerous compilation failures. Sometimes ccache
will retain stale code objects or corrupted files, which can lead to packages
that cannot be emerged. If this happens (if you receive errors like "File not
recognized: File truncated"), try recompiling the application with ccache
disabled (<c>FEATURES="-ccache"</c> in <path>/etc/make.conf</path>)
<e>before</e> reporting a bug. Unless you are doing development work, <e>do not
enable ccache</e>.
</warn>

</body>
</subsection>
<subsection>
<title>Installing ccache</title>
<body>

<p>
To install <c>ccache</c>, run <c>emerge ccache</c>:
</p>

<pre caption="Installing ccache">
# <i>emerge ccache</i>
</pre>

</body>
</subsection>
<subsection>
<title>Activating Portage Support</title>
<body>

<p>
Open <path>/etc/make.conf</path> and add <c>ccache</c> to the FEATURES variable.
Next, add a new variable called CCACHE_SIZE and set it to "2G":
</p>

<pre caption="Editing CCACHE_SIZE in /etc/make.conf">
CCACHE_SIZE="2G"
</pre>

<p>
To check if ccache functions, ask ccache to provide you with its statistics.
Because Portage uses a different ccache home directory, you need to set the
<c>CCACHE_DIR</c> variable as well:
</p>

<pre caption="Viewing ccache statistics">
# <i>CCACHE_DIR="/var/tmp/ccache" ccache -s</i>
</pre>

<p>
The <path>/var/tmp/ccache</path> location is Portage' default ccache home
directory; if you want to alter this setting you can set the <c>CCACHE_DIR</c>
variable in <path>/etc/make.conf</path>.
</p>

<p>
However, if you would run <c>ccache</c>, it would use the default location of
<path>${HOME}/.ccache</path>, which is why you needed to set the
<c>CCACHE_DIR</c> variable when asking for the (Portage) ccache statistics.
</p>

</body>
</subsection>
<subsection>
<title>Using ccache for non-Portage C Compiling</title>
<body>

<p>
If you would like to use ccache for non-Portage compilations, add
<path>/usr/lib/ccache/bin</path> to the beginning of your PATH variable (before
<path>/usr/bin</path>). This can be accomplished by editing
<path>.bash_profile</path> in your user's home directory. Using
<path>.bash_profile</path> is one way to define PATH variables.
</p>

<pre caption="Editing .bash_profile">
PATH="<i>/usr/lib/ccache/bin</i>:/opt/bin:${PATH}"
</pre>

</body>
</subsection>
</section>
<section>
<title>Binary Package Support</title>
<subsection>
<title>Creating Prebuilt Packages</title>
<body>

<p>
Portage supports the installation of prebuilt packages. Even though Gentoo does
not provide prebuilt packages by itself (except for the GRP snapshots) Portage
can be made fully aware of prebuilt packages.
</p>

<p>
To create a prebuilt package you can use <c>quickpkg</c> if the package is
already installed on your system, or <c>emerge</c> with the <c>--buildpkg</c> or
<c>--buildpkgonly</c> options.
</p>

<p>
If you want Portage to create prebuilt packages of every single package you
install, add <c>buildpkg</c> to the FEATURES variable.
</p>

<p>
More extended support for creating prebuilt package sets can be obtained with
<c>catalyst</c>. For more information on catalyst please read the <uri
link="/proj/en/releng/catalyst/faq.xml">Catalyst Frequently Asked
Questions</uri>.
</p>

</body>
</subsection>
<subsection>
<title>Installing Prebuilt Packages</title>
<body>

<p>
Although Gentoo doesn't provide one, you can create a central repository where 
you store prebuilt packages. If you want to use this repository, you need to 
make Portage aware of it by having the PORTAGE_BINHOST variable point to
it. For instance, if the prebuilt packages are on ftp://buildhost/gentoo:
</p>

<pre caption="Setting PORTAGE_BINHOST in /etc/make.conf">
PORTAGE_BINHOST="ftp://buildhost/gentoo"
</pre>

<p>
When you want to install a prebuilt package, add the <c>--getbinpkg</c> option
to the emerge command alongside of the <c>--usepkg</c> option. The former tells
emerge to download the prebuilt package from the previously defined server
while the latter asks emerge to try to install the prebuilt package first before
fetching the sources and compiling it.
</p>

<p>
For instance, to install <c>gnumeric</c> with prebuilt packages:
</p>

<pre caption="Installing the gnumeric prebuilt package">
# <i>emerge --usepkg --getbinpkg gnumeric</i>
</pre>

<p>
More information about emerge's prebuilt package options can be found in the
emerge man page:
</p>

<pre caption="Reading the emerge man page">
$ <i>man emerge</i>
</pre>

</body>
</subsection>
</section>
<section>
<title>Fetching Files</title>
<subsection>
<title>Parallel fetch</title>
<body>

<p>
When you are emerging a series of packages, Portage can fetch the source files
for the next package in the list even while it is compiling another package,
thus shortening compile times. To make use of this capability, add
"parallel-fetch" to your FEATURES. Note that this is on by default, so you
shouldn't need to specifically enable it.
</p>

</body>
</subsection>
<subsection>
<title>Userfetch</title>
<body>

<p>
When Portage is run as root, FEATURES="userfetch" will allow Portage to drop
root privileges while fetching package sources. This is a small security
improvement.
</p>

</body>
</subsection>
</section>
<section id="webrsync-gpg">
<title>Pulling Validated Portage Tree Snapshots</title>
<body>

<p>
As an administrator, you can opt to only update your local Portage tree with a
cryptographically validated Portage tree snapshot as released by the Gentoo
infrastructure. This ensures that no rogue rsync mirror is adding unwanted code
or packages in the tree you are downloading.
</p>

<p>
To configure Portage, first create a truststore in which you download and accept
the keys of the Gentoo Infrastructure responsible for signing the Portage tree
snapshots. Of course, if you want to, you can validate this GPG key as per the
<uri link="/doc/en/gnupg-user.xml#doc_chap2_sect4">proper guidelines</uri>
(like checking the key fingerprint). You can find the list of GPG keys used by
the release engineering team on their <uri
link="/proj/en/releng/index.xml">project page</uri>.
</p>

<!-- Key 0x239C75C4 is superceded by 0x96D8BF6D, but keep it in the documents
     for a while to ensure continuity -->

<pre caption="Creating a truststore for Portage">
# <i>mkdir -p /etc/portage/gpg</i>
# <i>chmod 0700 /etc/portage/gpg</i>
<comment>(... Substitute the keys with those mentioned on the release engineering site ...)</comment>
# <i>gpg --homedir /etc/portage/gpg --keyserver subkeys.pgp.net --recv-keys 0x239C75C4 0x96D8BF6D</i>
# <i>gpg --homedir /etc/portage/gpg --edit-key 0x239C75C4 trust</i>
# <i>gpg --homedir /etc/portage/gpg --edit-key 0x96D8BF6D trust</i>
</pre>

<p>
Next, edit <path>/etc/make.conf</path> and enable support for validating the
signed Portage tree snapshots (using <c>FEATURES="webrsync-gpg"</c>) and
disabling updating the Portage tree using the regular <c>emerge --sync</c>
method.
</p>

<pre caption="Updating Portage for signed tree validation">
FEATURES="webrsync-gpg"
PORTAGE_GPG_DIR="/etc/portage/gpg"
SYNC=""
</pre>

<p>
That's it. Next time you run <c>emerge-webrsync</c>, only the snapshots with
a valid signature will be expanded on your file system.
</p>


</body>
</section>

</sections>
1	<?xml version='1.0' encoding='UTF-8'?>
2	<!DOCTYPE sections SYSTEM "/dtd/book.dtd">
3
4	<!-- The content of this document is licensed under the CC-BY-SA license -->
5	<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
6
7	<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-working-features.xml,v 1.41 2012/03/28 22:44:07 nightmorph Exp $ -->
8
9	<sections>
10
11	<abstract>
12	Discover the features Portage has, such as support for distributed compiling,
13	ccache and more.
14	</abstract>
15
16	<version>6</version>
17	<date>2012-06-29</date>
18
19	<section>
20	<title>Portage Features</title>
21	<body>
22
23	<p>
24	Portage has several additional features that makes your Gentoo experience even
25	better. Many of these features rely on certain software tools that improve
26	performance, reliability, security, ...
27	</p>
28
29	<p>
30	To enable or disable certain Portage features you need to edit
31	<path>/etc/make.conf</path>'s <c>FEATURES</c> variable which contains the
32	various feature keywords, separated by white space. In several cases you
33	will also need to install the additional tool on which the feature relies.
34	</p>
35
36	<p>
37	Not all features that Portage supports are listed here. For a full overview,
38	please consult the <path>make.conf</path> man page:
39	</p>
40
41	<pre caption="Consulting the make.conf man page">
42	$ <i>man make.conf</i>
43	</pre>
44
45	<p>
46	To find out what FEATURES are default set, run <c>emerge --info</c> and search
47	for the FEATURES variable or grep it out:
48	</p>
49
50	<pre caption="Finding out the FEATURES that are already set">
51	$ <i>emerge --info \| grep FEATURES</i>
52	</pre>
53
54	</body>
55	</section>
56	<section>
57	<title>Distributed Compiling</title>
58	<subsection>
59	<title>Using distcc</title>
60	<body>
61
62	<p>
63	<c>distcc</c> is a program to distribute compilations across several, not
64	necessarily identical, machines on a network. The <c>distcc</c> client sends all
65	necessary information to the available distcc servers (running <c>distccd</c>)
66	so they can compile pieces of source code for the client. The net result is a
67	faster compilation time.
68	</p>
69
70	<p>
71	You can find more information about <c>distcc</c> (and how to have it work
72	with Gentoo) in our <uri link="/doc/en/distcc.xml">Gentoo Distcc
73	Documentation</uri>.
74	</p>
75
76	</body>
77	</subsection>
78	<subsection>
79	<title>Installing distcc</title>
80	<body>
81
82	<p>
83	Distcc ships with a graphical monitor to monitor tasks that your computer is
84	sending away for compilation. If you use Gnome then put 'gnome' in your USE
85	variable. However, if you don't use Gnome and would still like to have the
86	monitor then you should put 'gtk' in your USE variable.
87	</p>
88
89	<pre caption="Installing distcc">
90	# <i>emerge distcc</i>
91	</pre>
92
93	</body>
94	</subsection>
95	<subsection>
96	<title>Activating Portage Support</title>
97	<body>
98
99	<p>
100	Add <c>distcc</c> to the FEATURES variable inside <path>/etc/make.conf</path>.
101	Next, edit the MAKEOPTS variable to your liking. A known guideline is to fill in
102	"-jX" with X the number of CPUs that run <c>distccd</c> (including the current
103	host) plus one, but you might have better results with other numbers.
104	</p>
105
106	<p>
107	Now run <c>distcc-config</c> and enter the list of available distcc servers. For
108	a simple example we assume that the available DistCC servers are 192.168.1.102
109	(the current host), 192.168.1.103 and 192.168.1.104 (two "remote" hosts):
110	</p>
111
112	<pre caption="Configuring distcc to use three available distcc servers">
113	# <i>distcc-config --set-hosts "192.168.1.102 192.168.1.103 192.168.1.104"</i>
114	</pre>
115
116	<p>
117	Don't forget to run the <c>distccd</c> daemon as well:
118	</p>
119
120	<pre caption="Starting the distccd daemons">
121	# <i>rc-update add distccd default</i>
122	# <i>/etc/init.d/distccd start</i>
123	</pre>
124
125	</body>
126	</subsection>
127	</section>
128	<section>
129	<title>Caching Compilation</title>
130	<subsection>
131	<title>About ccache</title>
132	<body>
133
134	<p>
135	<c>ccache</c> is a fast compiler cache. When you compile a program, it will
136	cache intermediate results so that, whenever you recompile the same program, the
137	compilation time is greatly reduced. The first time you run ccache, it will be
138	much slower than a normal compilation. Subsequent recompiles should be faster.
139	ccache is only helpful if you will be recompiling the same application many
140	times; thus it's mostly only useful for software developers.
141	</p>
142
143	<p>
144	If you are interested in the ins and outs of ccache, please visit the
145	<uri link="http://ccache.samba.org">ccache homepage</uri>.
146	</p>
147
148	<warn>
149	<c>ccache</c> is known to cause numerous compilation failures. Sometimes ccache
150	will retain stale code objects or corrupted files, which can lead to packages
151	that cannot be emerged. If this happens (if you receive errors like "File not
152	recognized: File truncated"), try recompiling the application with ccache
153	disabled (<c>FEATURES="-ccache"</c> in <path>/etc/make.conf</path>)
154	<e>before</e> reporting a bug. Unless you are doing development work, <e>do not
155	enable ccache</e>.
156	</warn>
157
158	</body>
159	</subsection>
160	<subsection>
161	<title>Installing ccache</title>
162	<body>
163
164	<p>
165	To install <c>ccache</c>, run <c>emerge ccache</c>:
166	</p>
167
168	<pre caption="Installing ccache">
169	# <i>emerge ccache</i>
170	</pre>
171
172	</body>
173	</subsection>
174	<subsection>
175	<title>Activating Portage Support</title>
176	<body>
177
178	<p>
179	Open <path>/etc/make.conf</path> and add <c>ccache</c> to the FEATURES variable.
180	Next, add a new variable called CCACHE_SIZE and set it to "2G":
181	</p>
182
183	<pre caption="Editing CCACHE_SIZE in /etc/make.conf">
184	CCACHE_SIZE="2G"
185	</pre>
186
187	<p>
188	To check if ccache functions, ask ccache to provide you with its statistics.
189	Because Portage uses a different ccache home directory, you need to set the
190	<c>CCACHE_DIR</c> variable as well:
191	</p>
192
193	<pre caption="Viewing ccache statistics">
194	# <i>CCACHE_DIR="/var/tmp/ccache" ccache -s</i>
195	</pre>
196
197	<p>
198	The <path>/var/tmp/ccache</path> location is Portage' default ccache home
199	directory; if you want to alter this setting you can set the <c>CCACHE_DIR</c>
200	variable in <path>/etc/make.conf</path>.
201	</p>
202
203	<p>
204	However, if you would run <c>ccache</c>, it would use the default location of
205	<path>${HOME}/.ccache</path>, which is why you needed to set the
206	<c>CCACHE_DIR</c> variable when asking for the (Portage) ccache statistics.
207	</p>
208
209	</body>
210	</subsection>
211	<subsection>
212	<title>Using ccache for non-Portage C Compiling</title>
213	<body>
214
215	<p>
216	If you would like to use ccache for non-Portage compilations, add
217	<path>/usr/lib/ccache/bin</path> to the beginning of your PATH variable (before
218	<path>/usr/bin</path>). This can be accomplished by editing
219	<path>.bash_profile</path> in your user's home directory. Using
220	<path>.bash_profile</path> is one way to define PATH variables.
221	</p>
222
223	<pre caption="Editing .bash_profile">
224	PATH="<i>/usr/lib/ccache/bin</i>:/opt/bin:${PATH}"
225	</pre>
226
227	</body>
228	</subsection>
229	</section>
230	<section>
231	<title>Binary Package Support</title>
232	<subsection>
233	<title>Creating Prebuilt Packages</title>
234	<body>
235
236	<p>
237	Portage supports the installation of prebuilt packages. Even though Gentoo does
238	not provide prebuilt packages by itself (except for the GRP snapshots) Portage
239	can be made fully aware of prebuilt packages.
240	</p>
241
242	<p>
243	To create a prebuilt package you can use <c>quickpkg</c> if the package is
244	already installed on your system, or <c>emerge</c> with the <c>--buildpkg</c> or
245	<c>--buildpkgonly</c> options.
246	</p>
247
248	<p>
249	If you want Portage to create prebuilt packages of every single package you
250	install, add <c>buildpkg</c> to the FEATURES variable.
251	</p>
252
253	<p>
254	More extended support for creating prebuilt package sets can be obtained with
255	<c>catalyst</c>. For more information on catalyst please read the <uri
256	link="/proj/en/releng/catalyst/faq.xml">Catalyst Frequently Asked
257	Questions</uri>.
258	</p>
259
260	</body>
261	</subsection>
262	<subsection>
263	<title>Installing Prebuilt Packages</title>
264	<body>
265
266	<p>
267	Although Gentoo doesn't provide one, you can create a central repository where
268	you store prebuilt packages. If you want to use this repository, you need to
269	make Portage aware of it by having the PORTAGE_BINHOST variable point to
270	it. For instance, if the prebuilt packages are on ftp://buildhost/gentoo:
271	</p>
272
273	<pre caption="Setting PORTAGE_BINHOST in /etc/make.conf">
274	PORTAGE_BINHOST="ftp://buildhost/gentoo"
275	</pre>
276
277	<p>
278	When you want to install a prebuilt package, add the <c>--getbinpkg</c> option
279	to the emerge command alongside of the <c>--usepkg</c> option. The former tells
280	emerge to download the prebuilt package from the previously defined server
281	while the latter asks emerge to try to install the prebuilt package first before
282	fetching the sources and compiling it.
283	</p>
284
285	<p>
286	For instance, to install <c>gnumeric</c> with prebuilt packages:
287	</p>
288
289	<pre caption="Installing the gnumeric prebuilt package">
290	# <i>emerge --usepkg --getbinpkg gnumeric</i>
291	</pre>
292
293	<p>
294	More information about emerge's prebuilt package options can be found in the
295	emerge man page:
296	</p>
297
298	<pre caption="Reading the emerge man page">
299	$ <i>man emerge</i>
300	</pre>
301
302	</body>
303	</subsection>
304	</section>
305	<section>
306	<title>Fetching Files</title>
307	<subsection>
308	<title>Parallel fetch</title>
309	<body>
310
311	<p>
312	When you are emerging a series of packages, Portage can fetch the source files
313	for the next package in the list even while it is compiling another package,
314	thus shortening compile times. To make use of this capability, add
315	"parallel-fetch" to your FEATURES. Note that this is on by default, so you
316	shouldn't need to specifically enable it.
317	</p>
318
319	</body>
320	</subsection>
321	<subsection>
322	<title>Userfetch</title>
323	<body>
324
325	<p>
326	When Portage is run as root, FEATURES="userfetch" will allow Portage to drop
327	root privileges while fetching package sources. This is a small security
328	improvement.
329	</p>
330
331	</body>
332	</subsection>
333	</section>
334	<section id="webrsync-gpg">
335	<title>Pulling Validated Portage Tree Snapshots</title>
336	<body>
337
338	<p>
339	As an administrator, you can opt to only update your local Portage tree with a
340	cryptographically validated Portage tree snapshot as released by the Gentoo
341	infrastructure. This ensures that no rogue rsync mirror is adding unwanted code
342	or packages in the tree you are downloading.
343	</p>
344
345	<p>
346	To configure Portage, first create a truststore in which you download and accept
347	the keys of the Gentoo Infrastructure responsible for signing the Portage tree
348	snapshots. Of course, if you want to, you can validate this GPG key as per the
349	<uri link="/doc/en/gnupg-user.xml#doc_chap2_sect4">proper guidelines</uri>
350	(like checking the key fingerprint). You can find the list of GPG keys used by
351	the release engineering team on their <uri
352	link="/proj/en/releng/index.xml">project page</uri>.
353	</p>
354
355	<!-- Key 0x239C75C4 is superceded by 0x96D8BF6D, but keep it in the documents
356	for a while to ensure continuity -->
357
358	<pre caption="Creating a truststore for Portage">
359	# <i>mkdir -p /etc/portage/gpg</i>
360	# <i>chmod 0700 /etc/portage/gpg</i>
361	<comment>(... Substitute the keys with those mentioned on the release engineering site ...)</comment>
362	# <i>gpg --homedir /etc/portage/gpg --keyserver subkeys.pgp.net --recv-keys 0x239C75C4 0x96D8BF6D</i>
363	# <i>gpg --homedir /etc/portage/gpg --edit-key 0x239C75C4 trust</i>
364	# <i>gpg --homedir /etc/portage/gpg --edit-key 0x96D8BF6D trust</i>
365	</pre>
366
367	<p>
368	Next, edit <path>/etc/make.conf</path> and enable support for validating the
369	signed Portage tree snapshots (using <c>FEATURES="webrsync-gpg"</c>) and
370	disabling updating the Portage tree using the regular <c>emerge --sync</c>
371	method.
372	</p>
373
374	<pre caption="Updating Portage for signed tree validation">
375	FEATURES="webrsync-gpg"
376	PORTAGE_GPG_DIR="/etc/portage/gpg"
377	SYNC=""
378	</pre>
379
380	<p>
381	That's it. Next time you run <c>emerge-webrsync</c>, only the snapshots with
382	a valid signature will be expanded on your file system.
383	</p>
384
385
386	</body>
387	</section>
388
389	</sections>