GNU Alive
1 Introduction
1.1 Features
1.2 History
1.2.1 Phase 1
1.2.2 Phase 2
2 Invoking alive
3 Configuration
3.1 Generally Sexp-ing
3.2 hosts
3.3 period
Appendix A GNU Software
Appendix B GNU Free Documentation License
Index
GNU Alive
*********
This manual is for GNU Alive (version 2.0.5, 1 January 2022).
Copyright © 2012, 2013, 2020–2022 Thien-Thi Nguyen
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.3 or any later version published by the Free Software
Foundation; with no Invariant Sections, with no Front-Cover Texts,
and with no Back-Cover Texts. A copy of the license is included in
the appendix entitled “GNU Free Documentation License”.
1 Introduction
**************
Sometimes it’s not enough to simply “get on the net”; what’s important
is to *stay on* the net. If the network is depressed, it might start
ignoring you. You can use GNU Alive to cheer it up. But, first things
first. Do you know what this command:
ping -i 149 IPADDR
does? If you answered “yes” and don’t mind typing that command into a
shell, then you *do not* need GNU Alive, as its functionality is roughly
equivalent to that command. In this case, go ahead and save yourself
some time and disk space and remove this package from your computer!
If you answered “no” instead, perhaps that’s because you know what
‘ping IPADDR’ does, but are not so sure about ‘-i 149’. Well, it turns
out that ‘-i N’ means repeat the ping every N seconds, instead of every
second, the default. So now you know, and can blithely proceed to
remove GNU Alive from your computer. Go ahead, what are you waiting
for?
Still here? Fine. You must be curious, then, about the “roughly
equivalent” functionality mentioned above. Surely there must be
*something* to recommend GNU Alive. Was such profligate duplication
always so?
1.1 Features
============
As previously established (*note Introduction::), GNU Alive is a package
that provides a command-line program to periodically make network
contact with (aka “ping”) a specified host. This section describes some
differences between ‘ping’ and ‘alive’ (the program).
superficial
===========
takes ‘--help’, ‘--version’
Like all proper GNU programs, ‘alive’ supports these options,
displaying the requested information to stdout and exiting
successfully. *Note Invoking alive::.
Note that Inetutils (*note GNU Software::) ping also supports these
options, as it is also a proper GNU program. Other ping programs
may or may not.
no arguments
To keep things simple and consistent, ‘alive’ takes no arguments,
and instead reads configuration information from files in the
“config directory”, by default ‘$HOME/.alive.d/’.
If that dir does not exist and your system has ‘xdgdirs’(1), then
the the config directory is taken to be what ‘xdgdirs alive’
returns for ‘config-home’ (you can influence this by setting env
var ‘XDG_CONFIG_HOME’).
In any case, if the config dir or those files don’t exist, ‘alive’
uses reasonable defaults.
reconfiguration without restart
Each configuration file is rescanned at the top of every loop
iteration if its modification time differs from the last check.
This means it’s enough to edit a file (and wait); no need to
restart the program. *Note Configuration::.
multiple hosts / no hosts
If you specify more than one host, ‘alive’ contacts them in a
round-robin fashion. This reduces the annoyance level of some
network administrators—always a good idea.
On the other hand, if you don’t specify any hosts, ‘alive’ contacts
localhost (typically, ‘127.0.0.1’).
randomized period
The default “period”, i.e., time between successive contacts, is a
random number of seconds in the range 149 to 420, inclusive.
profound
========
source code available at runtime
All GNU programs are distributed as source code, of course, but GNU
Alive goes further; the source code is also available when you run
the program.
This is because ‘alive’ is implemented as a “script”, a sequence of
textual instructions for an “interpreter” program to read and
evaluate, rather than a binary file.
Most users don’t care about runtime access to source code, but
perhaps you are not like most users.
implementation language: Guile Scheme
configuration language: sexps
GNU Alive uses Guile Scheme (*note GNU Software::) as the
implementation language.
Each configuration file is a series of “sexps”, or structured
expressions, amenable to the Scheme ‘read’ procedure. (Actually,
the syntax is designed to be a subset of what Scheme ‘read’ can
handle, to be friendly also to Emacs Lisp ‘read’.)
Most programmers don’t care about sexps, but perhaps you are not
like most programmers.
---------- Footnotes ----------
(1) home page:
1.2 History
===========
This section describes the evolution of GNU Alive purpose and design.
There are two major development phases, both completely independent of
the other.
1.2.1 Phase 1
-------------
[TODO: Describe evolution, as advertized—the following is only a
description of the state immediately prior to beginning of phase 2
(*note Phase 2::).]
Originally, GNU Alive was called ‘qadsl’, and had two purposes: to
auto-login to certain Swedish dial-up ISPs(1); and to maintain the
connection via periodic network traffic. Its authors and maintainers
were: Jakob "Kuba" Stasilowicz, Peter Strömberg, Kenth Garlöv, Joachim
Nilsson, and Jakob Eriksson.
It was implemented in C and ported to GNU/Hurd, several GNU/Linux
variants, NetBSD, and FreeBSD. It used a text-based configuration file
format for server name and port, user name, login, password, keepalive
daemon type and policy, and so forth. Configuration could be done at
system (in ‘/etc’) level, user (under ‘~’) level, and with corresponding
command-line options.
There were two “keepalive types”, i.e., methods for generating
network traffic: HTTP and “ping” (in spirit, not really ICMP). There was
debug, pidfile, syslog support. Once running, the daemon could be
queried and commanded by another invocation.
The distribution included an example configuration file, installed in
‘$(sysconfdir)’; an info-format manual, for ‘$(infodir)’; and two
manpages: ‘alive.8’ and ‘alive.conf.5’, installed under (in the
appropriate subdirectory of) ‘$(mandir)’.
The last release of phase 1 GNU Alive was 1.4.0 (2005-02-22),
released under GNU GPL v2+ (like all previous releases). There was a
small change afterwards that was never released:
Author: Joachim Nilsson
Date: 2005-11-19 12:23:22 +0000
Attempt to lower the impact of non-responding login servers.
Don't sleep too long before retrying, it's OK to fail.
src/http.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
The source code comprised a handful of C files for low-level internals
(cross-platform support, e.g., ‘strcasecmp’); a pair of Yacc/Lex input
files with glue C code, to implement the configuration file parser
module; and 19 ‘.h’ and ‘.c’ files, to implement the program itself.
Curiously, the usual mass of Autotools flotsam (i.e., ‘configure’
script et al, *note GNU Software::) was checked into the repository.
Release 1.4.0 was prepared using GNU Autoconf 2.59 and GNU Automake
1.8.5.
---------- Footnotes ----------
(1) Some contemporary projects in the same functionality space:
TeliaTalker, CiC Login, ARAW, qADSL 1.2.x (from a previous maintainer),
TeliaADSLCon, Telia ADSL Connection Keeper, “Clever use of netcat”, LF
Connection Keeper. Most of these are defunct or obsolete nowadays.
1.2.2 Phase 2
-------------
After several years without activity or release (*note Phase 1::), in
2012 Thien-Thi Nguyen volunteered to adopt GNU Alive with the intent to
drop the auto-login functionality, leaving only the periodic ping, and
furthermore, to do a rewrite from scratch. (This is why his name
appears on the copyright notices, solely.)
Phase 2 GNU Alive is released under GNU GPL v3+, with a new feature
set (*note Features::).
2 Invoking alive
****************
Running ‘alive’ is easy. Simply type ‘alive’ at the shell prompt
followed by . You can use the shell’s i/o redirection facilities
to filter/suppress the output, and its job control facilities to have
‘alive’ execute in the background. For example, with GNU Bash (*note
GNU Software::):
$ alive >/dev/null &
Two other modes of operation are available:
$ alive --version
$ alive --help
That’s it! Quite boring, no? The real fun lies in playing with the
configuration, either before starting ‘alive’, or while it runs. *Note
Configuration::.
Additionally, ‘alive’ responds to certain signals in a more or less
well-defined manner. To send it a signal, first note its “pid” (process
id), displayed on the first line output:
$ alive
alive: 2012-08-11 16:24:26 restart (pid 9731)
[...]
The pid in this example is ‘9731’. Next, use the command-line utility
‘kill’:
$ kill -INT 9731
or Emacs command ‘signal-process’:
M-x signal-process RET 9731 RET 2 RET
specifying this pid and the signal to send. All unhandled signals (not
described in the following table) will cause ‘alive’ to die
unceremoniously. To see a list, try ‘kill -l’. Handled signals, on the
other hand, elicit an acknowledgement on stdout, e.g., ‘received signal
2 (SIGINT)’.
‘SIGALRM’
Interrupt the current ‘sleep(2)’. This is useful if you change the
configuration and don’t want to wait for the next iteration.
‘SIGHUP’
‘SIGUSR1’
Restart. This is useful if you forget the pid.
‘SIGINT’
‘SIGQUIT’
‘SIGTERM’
Shut down, i.e., display ‘exiting’ and exit successfully.
3 Configuration
***************
You can modify ‘alive’ behavior (even while it runs), by writing simple
sexps into text files under the config directory (*note Features::).
Information for a “configuration item” FOO is written in file ‘foo’.
3.1 Generally Sexp-ing
======================
The file format for the configuration items (*note Configuration::) is
composed of comments, structured expressions, and whitespace.
comments
A comment begins with ‘;’ (semicolon) and goes to the end of the
line. If you use Emacs, you can add the comment:
;; -*- scheme -*-
on the first line to make comments appear differently, presuming
syntax highlighting support is enabled.
structured expressions
A structured expression, for the purposes of GNU Alive, is one of:
integer
A decimal number (usually). For instance, ‘42’. GNU Alive
will also accept ‘#b101010’ (binary), ‘#o52’ (octal) and
‘#x2A’ (hexadecimal) without complaint.
symbol
A contiguous sequence of non-whitespace characters that do not
include ‘()’ (parentheses), ‘,’ (comma), ‘'’ (apopostrophe,
also known as single-quote), or ‘"’ (double-quote). For
instance, ‘www.gnu.org’.
That’s it!
whitespace
Everything else, that is, all the stuff between comments and
structured expressions, is whitespace.
3.2 hosts
=========
The ‘hosts’ configuration item specifies who to ping. Each symbol is
either a host name or IP address.
;;; hosts (-*- scheme -*-)
;; gateway
10.0.0.1
;; various hosts, increasingly further out
foo.local-lan
bar.site-lan
baz.example.com
;;; hosts ends here
3.3 period
==========
The ‘period’ configuration item specifies how long to wait between
pings. The units are (integer) seconds. If there is one integer,
‘alive’ uses it as a fixed period. If there are two, the first must be
less than or equal than the second, and ‘alive’ chooses a random number
between (inclusively) the two.
;;; period (-*- scheme -*-)
;; quickly
; 3
;; languidly
; 391
;; randomly, but not too quickly
149 420
;;; period ends here
Appendix A GNU Software
***********************
This appendix describes some other GNU software used in the maintenance,
design and implementation of GNU Alive. For more information about the
GNU project, please visit .
Inetutils —
Inetutils provides several command-line utilities for working with
a network capable of speaking “IP” (Internet Protocol). Most
relevant to GNU Alive is ‘ping’, which ‘alive’ invokes directly, to
compose, send, receive and interpret the actual network (on the
wire) packets; and “emulates” indirectly (i.e., sleeping and
looping, as for ‘ping -i PERIOD’).
Guile —
Guile provides the Scheme interpreter that actually executes the
‘alive’ script, a crucial role certainly. The design choice to use
sexps for configuration items is also informed by Guile. Less
known perhaps is that Guile plays a part also in the GNU Alive
maintenance; e.g., several Scheme programs and modules are used to
prepare its home page.
Autoconf —
Automake —
These are indispensable for maintenance. Autoconf is reponsible
for the ‘configure’ script, and Automake is responsible for
generating the various ‘Makefile.in’ files that uphold the rest of
the standard GNU build/installation system.
Bash —
GNU Alive writes to standard output, and thus is amenable to the
parent shell’s i/o redirection facilities. We use Bash to document
an example of this (*note Invoking alive::).
Emacs —
Although Alive does not use Emacs directly, the configuration items
can be easily manipulated by Emacs (*note Configuration::), and
Emacs has good support for managing child processes, like Bash.
Why not consider writing a user interface to Alive for Emacs?
Appendix B GNU Free Documentation License
*****************************************
Version 1.3, 3 November 2008
Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document “free” in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by others.
This License is a kind of “copyleft”, which means that derivative
works of the document must themselves be free in the same sense.
It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a
free program should come with manuals providing the same freedoms
that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless
of subject matter or whether it is published as a printed book. We
recommend this License principally for works whose purpose is
instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium,
that contains a notice placed by the copyright holder saying it can
be distributed under the terms of this License. Such a notice
grants a world-wide, royalty-free license, unlimited in duration,
to use that work under the conditions stated herein. The
“Document”, below, refers to any such manual or work. Any member
of the public is a licensee, and is addressed as “you”. You accept
the license if you copy, modify or distribute the work in a way
requiring permission under copyright law.
A “Modified Version” of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.
A “Secondary Section” is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document’s overall
subject (or to related matters) and contains nothing that could
fall directly within that overall subject. (Thus, if the Document
is in part a textbook of mathematics, a Secondary Section may not
explain any mathematics.) The relationship could be a matter of
historical connection with the subject or with related matters, or
of legal, commercial, philosophical, ethical or political position
regarding them.
The “Invariant Sections” are certain Secondary Sections whose
titles are designated, as being those of Invariant Sections, in the
notice that says that the Document is released under this License.
If a section does not fit the above definition of Secondary then it
is not allowed to be designated as Invariant. The Document may
contain zero Invariant Sections. If the Document does not identify
any Invariant Sections then there are none.
The “Cover Texts” are certain short passages of text that are
listed, as Front-Cover Texts or Back-Cover Texts, in the notice
that says that the Document is released under this License. A
Front-Cover Text may be at most 5 words, and a Back-Cover Text may
be at most 25 words.
A “Transparent” copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images composed
of pixels) generic paint programs or (for drawings) some widely
available drawing editor, and that is suitable for input to text
formatters or for automatic translation to a variety of formats
suitable for input to text formatters. A copy made in an otherwise
Transparent file format whose markup, or absence of markup, has
been arranged to thwart or discourage subsequent modification by
readers is not Transparent. An image format is not Transparent if
used for any substantial amount of text. A copy that is not
“Transparent” is called “Opaque”.
Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format,
SGML or XML using a publicly available DTD, and standard-conforming
simple HTML, PostScript or PDF designed for human modification.
Examples of transparent image formats include PNG, XCF and JPG.
Opaque formats include proprietary formats that can be read and
edited only by proprietary word processors, SGML or XML for which
the DTD and/or processing tools are not generally available, and
the machine-generated HTML, PostScript or PDF produced by some word
processors for output purposes only.
The “Title Page” means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the
material this License requires to appear in the title page. For
works in formats which do not have any title page as such, “Title
Page” means the text near the most prominent appearance of the
work’s title, preceding the beginning of the body of the text.
The “publisher” means any person or entity that distributes copies
of the Document to the public.
A section “Entitled XYZ” means a named subunit of the Document
whose title either is precisely XYZ or contains XYZ in parentheses
following text that translates XYZ in another language. (Here XYZ
stands for a specific section name mentioned below, such as
“Acknowledgements”, “Dedications”, “Endorsements”, or “History”.)
To “Preserve the Title” of such a section when you modify the
Document means that it remains a section “Entitled XYZ” according
to this definition.
The Document may include Warranty Disclaimers next to the notice
which states that this License applies to the Document. These
Warranty Disclaimers are considered to be included by reference in
this License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and
has no effect on the meaning of this License.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License
applies to the Document are reproduced in all copies, and that you
add no other conditions whatsoever to those of this License. You
may not use technical measures to obstruct or control the reading
or further copying of the copies you make or distribute. However,
you may accept compensation in exchange for copies. If you
distribute a large enough number of copies you must also follow the
conditions in section 3.
You may also lend copies, under the same conditions stated above,
and you may publicly display copies.
3. COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly
have printed covers) of the Document, numbering more than 100, and
the Document’s license notice requires Cover Texts, you must
enclose the copies in covers that carry, clearly and legibly, all
these Cover Texts: Front-Cover Texts on the front cover, and
Back-Cover Texts on the back cover. Both covers must also clearly
and legibly identify you as the publisher of these copies. The
front cover must present the full title with all words of the title
equally prominent and visible. You may add other material on the
covers in addition. Copying with changes limited to the covers, as
long as they preserve the title of the Document and satisfy these
conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto
adjacent pages.
If you publish or distribute Opaque copies of the Document
numbering more than 100, you must either include a machine-readable
Transparent copy along with each Opaque copy, or state in or with
each Opaque copy a computer-network location from which the general
network-using public has access to download using public-standard
network protocols a complete Transparent copy of the Document, free
of added material. If you use the latter option, you must take
reasonably prudent steps, when you begin distribution of Opaque
copies in quantity, to ensure that this Transparent copy will
remain thus accessible at the stated location until at least one
year after the last time you distribute an Opaque copy (directly or
through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of
the Document well before redistributing any large number of copies,
to give them a chance to provide you with an updated version of the
Document.
4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you
release the Modified Version under precisely this License, with the
Modified Version filling the role of the Document, thus licensing
distribution and modification of the Modified Version to whoever
possesses a copy of it. In addition, you must do these things in
the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title
distinct from that of the Document, and from those of previous
versions (which should, if there were any, be listed in the
History section of the Document). You may use the same title
as a previous version if the original publisher of that
version gives permission.
B. List on the Title Page, as authors, one or more persons or
entities responsible for authorship of the modifications in
the Modified Version, together with at least five of the
principal authors of the Document (all of its principal
authors, if it has fewer than five), unless they release you
from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license
notice giving the public permission to use the Modified
Version under the terms of this License, in the form shown in
the Addendum below.
G. Preserve in that license notice the full lists of Invariant
Sections and required Cover Texts given in the Document’s
license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled “History”, Preserve its Title,
and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on the
Title Page. If there is no section Entitled “History” in the
Document, create one stating the title, year, authors, and
publisher of the Document as given on its Title Page, then add
an item describing the Modified Version as stated in the
previous sentence.
J. Preserve the network location, if any, given in the Document
for public access to a Transparent copy of the Document, and
likewise the network locations given in the Document for
previous versions it was based on. These may be placed in the
“History” section. You may omit a network location for a work
that was published at least four years before the Document
itself, or if the original publisher of the version it refers
to gives permission.
K. For any section Entitled “Acknowledgements” or “Dedications”,
Preserve the Title of the section, and preserve in the section
all the substance and tone of each of the contributor
acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document, unaltered
in their text and in their titles. Section numbers or the
equivalent are not considered part of the section titles.
M. Delete any section Entitled “Endorsements”. Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled
“Endorsements” or to conflict in title with any Invariant
Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no
material copied from the Document, you may at your option designate
some or all of these sections as invariant. To do this, add their
titles to the list of Invariant Sections in the Modified Version’s
license notice. These titles must be distinct from any other
section titles.
You may add a section Entitled “Endorsements”, provided it contains
nothing but endorsements of your Modified Version by various
parties—for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of
a standard.
You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end of
the list of Cover Texts in the Modified Version. Only one passage
of Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity. If the Document
already includes a cover text for the same cover, previously added
by you or by arrangement made by the same entity you are acting on
behalf of, you may not add another; but you may replace the old
one, on explicit permission from the previous publisher that added
the old one.
The author(s) and publisher(s) of the Document do not by this
License give permission to use their names for publicity for or to
assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for
modified versions, provided that you include in the combination all
of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your
combined work in its license notice, and that you preserve all
their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name
but different contents, make the title of each such section unique
by adding at the end of it, in parentheses, the name of the
original author or publisher of that section if known, or else a
unique number. Make the same adjustment to the section titles in
the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections Entitled
“History” in the various original documents, forming one section
Entitled “History”; likewise combine any sections Entitled
“Acknowledgements”, and any sections Entitled “Dedications”. You
must delete all sections Entitled “Endorsements.”
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the
rules of this License for verbatim copying of each of the documents
in all other respects.
You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert
a copy of this License into the extracted document, and follow this
License in all other respects regarding verbatim copying of that
document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of a
storage or distribution medium, is called an “aggregate” if the
copyright resulting from the compilation is not used to limit the
legal rights of the compilation’s users beyond what the individual
works permit. When the Document is included in an aggregate, this
License does not apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document’s Cover Texts may be placed
on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic
form. Otherwise they must appear on printed covers that bracket
the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section
4. Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also
include the original English version of this License and the
original versions of those notices and disclaimers. In case of a
disagreement between the translation and the original version of
this License or a notice or disclaimer, the original version will
prevail.
If a section in the Document is Entitled “Acknowledgements”,
“Dedications”, or “History”, the requirement (section 4) to
Preserve its Title (section 1) will typically require changing the
actual title.
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense, or distribute it is void,
and will automatically terminate your rights under this License.
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the
copyright holder fails to notify you of the violation by some
reasonable means prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from
that copyright holder, and you cure the violation prior to 30 days
after your receipt of the notice.
Termination of your rights under this section does not terminate
the licenses of parties who have received copies or rights from you
under this License. If your rights have been terminated and not
permanently reinstated, receipt of a copy of some or all of the
same material does not give you any rights to use it.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of
the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
.
Each version of the License is given a distinguishing version
number. If the Document specifies that a particular numbered
version of this License “or any later version” applies to it, you
have the option of following the terms and conditions either of
that specified version or of any later version that has been
published (not as a draft) by the Free Software Foundation. If the
Document does not specify a version number of this License, you may
choose any version ever published (not as a draft) by the Free
Software Foundation. If the Document specifies that a proxy can
decide which future versions of this License can be used, that
proxy’s public statement of acceptance of a version permanently
authorizes you to choose that version for the Document.
11. RELICENSING
“Massive Multiauthor Collaboration Site” (or “MMC Site”) means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works. A
public wiki that anybody can edit is an example of such a server.
A “Massive Multiauthor Collaboration” (or “MMC”) contained in the
site means any set of copyrightable works thus published on the MMC
site.
“CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.
“Incorporate” means to publish or republish a Document, in whole or
in part, as part of another Document.
An MMC is “eligible for relicensing” if it is licensed under this
License, and if all works that were first published under this
License somewhere other than this MMC, and subsequently
incorporated in whole or in part into the MMC, (1) had no cover
texts or invariant sections, and (2) were thus incorporated prior
to November 1, 2008.
The operator of an MMC Site may republish an MMC contained in the
site under CC-BY-SA on the same site at any time before August 1,
2009, provided the MMC is eligible for relicensing.
ADDENDUM: How to use this License for your documents
====================================================
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:
Copyright (C) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover
Texts, replace the “with...Texts.” line with this:
with the Invariant Sections being LIST THEIR TITLES, with
the Front-Cover Texts being LIST, and with the Back-Cover Texts
being LIST.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit
their use in free software.
Index
*****
* Menu:
* Autoconf: GNU Software. (line 381)
* Automake: GNU Software. (line 382)
* Bash: GNU Software. (line 389)
* configuration: Configuration. (line 276)
* Emacs: GNU Software. (line 395)
* features: Features. (line 58)
* fun: Configuration. (line 276)
* Guile: GNU Software. (line 372)
* hosts configuration item: hosts. (line 318)
* Inetutils: GNU Software. (line 363)
* invocation: Invoking alive. (line 220)
* non-recommendation: Introduction. (line 33)
* period configuration item: period. (line 336)
* qadsl: Phase 1. (line 152)
* software, GNU: GNU Software. (line 358)
* structured expression: Generally Sexp-ing. (line 283)