os-utils.texi

@c -*-texinfo-*- @c @c Copyright (C) 2002, 2003 Free Software Foundation, Inc. @c Copyright (C) 2003 Jake Colman @c @c @setfilename os-utils.info @settitle Operating System Utilities for XEmacs @ifinfo @dircategory XEmacs Editor @direntry * OS Utilities: (os-utils). Operating System Utilities for XEmacs. @end direntry @end ifinfo

@copying This manual is part of XEmacs.

XEmacs 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, or (at your option) any later version.

XEmacs 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 XEmacs; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. @end copying

@node Top, Copying, (dir), (dir) @chapter The Operating System Utilities Package

@ifinfo This Info file contains the manual for the Operating System Utilities package. @end ifinfo

The node name for each entry in the menu is the name of the elisp file containing the code that implements the functionality described. It is highly recommended that you briefly peruse the elisp source code since it can provide valuable information on usage and technique. This can easily be done by typing @code{C-x 4 l <filename> RET} where <filename> is the name of the elisp file to be loaded.

@menu * Copying:: Why this manual is GPL, and what that means

Archive Management * tar-mode:: Simple Editing of TAR Files * arc-mode:: Simple Editing of Archives

Compression/Decompression * crypt:: Handling for Compressed and Encrypted Files * jka-compr:: Reading/Writing/Loading Compressed Files * uncompress:: Auto-Decompression Hook for Visiting .Z Files

Communications * telnet:: Execute a Telnet Session From Within an Emacs Buffer * ssh:: Remote Login Interface Using SSH * ftelnet:: Remote Login Interface Using Telnet * rlogin:: Remote Login Interface Using rlogin * mchat:: Multicast Chatting * kermit:: Using Shell Mode With Kermit * terminal:: Terminal Emulator

Miscellaneous * spell:: Spelling Correction * background:: Fun With Background Jobs * inf-lisp:: Inferior-Lisp Mode * ledit:: ledit

Appendices: * XEmacs License:: The GNU General Public License @end menu

@node Copying, tar-mode, Top, Top @chapter Copying

This document may be redistributed, verbatim or in modified form, under the terms of the GNU General Public License, version 2 or any later version. The same terms apply to the libraries it documents. A copy of the General Public License is provided as an Appendix.

Most XEmacs documentation has its own license, which is an ancestor of the GNU Free Documentation License (@dfn{FDL}), and whose terms are quite similar to those imposed by GNU on Emacs documentation. Why is this manual licensed differently (under the GNU General Public License, or @dfn{GPL}), and why does it have to be distributed separately from the XEmacs User's Guide and the XEmacs Lisp Reference Manual?

Taking the second question first, XEmacs is @dfn{community-owned} software. That is, unlike GNU Emacs, there is no monopoly copyright holder. Many of us, including the original Lucid authors, have contributed our copyrights to the Free Software Foundation (FSF), and of course much content is derived from GNU Emacs, and therefore is held by the FSF. Another large chunk is held by Sun Microsystems, and a few individual authors hold copyright to thousands of lines each. But many individuals hold copyright to only a few dozen lines. Like the Linux kernel, copyright ownership is distributed throughout a community.

However, its license is ``copyleft,'' @emph{i.e.}, it @emph{requires} that you redistribute it under terms @emph{identical} to those under which you received it, unless you have explicit permission of the copyright holder. Because of the multiple owners, determining the ownership of any given part of XEmacs is tedious, and perhaps impossible. For practical purposes, then, the license of any substantial chunk of existing XEmacs content cannot be changed, except to a later version of the GPL, for those parts under GPL. (That is due to the @emph{explicit} permission to change to a later version of the GPL, present in every file of XEmacs.)

Unfortunately, this severe restriction means that the GPL, FDL, and the XEmacs documentation license (@dfn{XDL}) are @emph{mutually incompatible}. That is, content licensed under any of the GPL, FDL, or XDL @emph{may not} be mixed with content licensed under either of the other two without changing the license of some of the content. But this requires permission of the copyright holder, which is often difficult or impossible to get.

For example, you @emph{may not} take comments or docstrings from XEmacs code and add them to the Lispref to mend a gap in the latter's coverage. You @emph{may not} copy text from the Lispref into docstrings in the code. And you @emph{may not} copy text from the GNU Emacs Lisp Reference to the XEmacs Lisp Reference Manual. (In this case it is at least trivial to ask permission, although it is rather unclear whether it would be granted.)

In fact, parts of this document were derived by copying from XEmacs code under the GPL, without any further permission from the authors. Thus, this document must be distributed under the GPL, as a ``volume'' separate from the XEmacs documentation under the XDL. Note that the ``mere aggregation'' clauses allow us to distribute in the same tarball. But incorporating it as a node in the Lispref is prohibited, even if done by inclusion.

A bit of advocacy:

If you look carefully at the additional restrictions imposed by the soi-disant "free" documentation licenses, you discover that they are simply proprietary restrictions guaranteeing a certain amount of @emph{unpaid} political advertising to the Free Software Foundation and GNU Project (and in the case of the FDL, this is extended to commercial advertising by authors of original or derived works). Whether this is ``ethically justified'' or not is a difficult question. What is certain is that there is little social benefit to these terms (since the license documents themselves contain the advocacy and must be included with any distribution).

I conclude it makes sense for XEmacs to reduce its restrictions, where possible, to the ``least common denominator,'' the GNU General Public License.

@node tar-mode, arc-mode, Copying, Top @chapter Simple Editing of TAR Files

This package attempts to make dealing with Unix 'tar' archives easier. When this code is loaded, visiting a file whose name ends in '.tar' will cause the contents of that archive file to be displayed in a Dired-like listing. It is then possible to use the customary Dired keybindings to extract sub-files from that archive, either by reading them into their own editor buffers, or by copying them directly to arbitrary files on disk. It is also possible to delete sub-files from within the tar file and write the modified archive back to disk, or to edit sub-files within the archive and re-insert the modified files into the archive. See the documentation string of @code{tar-mode} for more info.

To configure this package, type:

@example
M-x customize-group RET tar RET @end example

@node arc-mode, crypt, tar-mode, Top @chapter Simple Editing of Archives

This library not documented. Please contribute!

To configure this package, type:

@example
M-x customize-group RET archive RET @end example

@node crypt, jka-compr, arc-mode, Top @chapter Handling for Compressed and Encrypted Files

The basic purpose of this package of Lisp functions is to recognize automatically encrypted and encoded (i.e., compressed) files when they are first visited or written. The BUFFER corresponding to the file is decoded and/or decrypted before it is presented to the user. The file itself is unchanged on the disk. When the buffer is subsequently saved to disk, a hook function re-encodes the buffer before the actual disk write takes place.

This package recognizes all sorts of compressed files by a magic number at the beginning of these files but uses a heuristic to detect encrypted files. If you are asked for an encryption key for a file that is in fact not encrypted, just hit RET and the file will be accepted as is, and the crypt minor mode will not be entered.

Other types of encoding programs may be added to this package by using the variable @code{crypt-encoding-alist} which contains a table of encoding programs such as @code{compress}, @code{gzip} (GNU zip), @code{freeze}, and @code{compact}.

This new extended version of crypt now monitors the filename extensions of buffers that are written out using @code{write-file} (@kbd{C-x C-w}). If the filename extension matches one of the extensions listed in @code{crypt-encoding-alist}, then this package will write the file out using the corresponding encoding (compression) method. This is done whether or not the buffer originated from a previously encoded (compressed) file.

Thus, if the user is editing a file that may or may not have been encoded originally (e.g., @file{foobar.Z} or @file{foobar}) and decides to write it to a different file (e.g., @file{barfoo} or @file{barfoo.z} or @file{barfoo.C}). This package will examine the filename extension and write the buffer in plain format or an alternate encoding (compression) format by searching through the entries in the table of encoding methods @code{crypt-encoding-alist}. This change in encoding state is done automatically if the variable @code{crypt-auto-write-buffer} is t otherwise the user is asked.

To use this package, put the line @code{(require 'crypt)} in your initialization file. Do not bother trying to autoload this file; this package uses @code{find-file} and @code{write-file} hooks and thus should be loaded the first time you visit any sort of file. Any package loaded after this one that appends something to @code{write-file-hooks} will not be executed because this package writes out the file. Other packages that append to @code{write-file-hooks} should either be modified to prepend to that hook or be loaded before this one (preferably the former).

NOTE: encryption users should set @code{crypt-encryption-type} to one of the values in @code{crypt-encryption-alist}.

To configure this package, type:

@example
M-x customize-group RET compression RET @end example

@node jka-compr, uncompress, crypt, Top @chapter Reading/Writing/Loading Compressed Files

This package implements low-level support for reading, writing, and loading compressed files. It hooks into the low-level file I/O functions (including @code{write-region} and @code{insert-file-contents}) so that they automatically compress or uncompress a file if the file appears to need it (based on the extension of the file name). Packages like Rmail, VM, GNUS, and Info should be able to work with compressed files without modification.

The operation of this package should be transparent to the user (except for messages appearing when a file is being compressed or uncompressed).

The variable, @code{jka-compr-compression-info-list} can be used to customize @code{jka-compr} to work with other compression programs. The default value of this variable allows @code{jka-compr} to work with Unix compress and gzip.

To activate this package, add the following to your initialization file:

@example
(toggle-auto-compression 1 t) ; enable compression/decompression @end example

To configure this package, type:

@example
M-x customize-group RET jka-compr RET @end example

@node uncompress, telnet, jka-compr, Top @chapter Auto-Decompression Hook for Visiting .Z Files

This package can be used to arrange for automatic uncompress of compressed files when they are visited. All that's necessary is to load it. This can conveniently be done from your initialization file.

@code{M-x auto-compression-mode} is a more modern replacement for this package.

@node telnet, ssh, uncompress, Top @chapter Execute a Telnet Session From Within an Emacs Buffer

This mode is intended to be used for telnet or rsh to a remote host; @code{telnet} and @code{rsh} are the two entry points. Multiple telnet or rsh sessions are supported.

Normally, input is sent to the remote telnet/rsh line-by-line, as you type @kbd{RET} or @kbd{LFD}. @kbd{C-c C-c} sends a @kbd{C-c} to the remote immediately; @kbd{C-c C-z} sends @kbd{C-z} immediately. @kbd{C-c C-q} followed by any character sends that character immediately.

All @kbd{RET} characters are filtered out of the output coming back from the remote system. The mode tries to do other useful translations based on what it sees coming back from the other system before the password query. It knows about UNIX, ITS, TOPS-20 and Explorer systems.

You can use the global @code{telnet-host-properties} to associate a telnet program and login name with each host you regularly telnet to.

To configure this package, type:

@example
M-x customize-group RET telnet RET @end example

@node ssh, ftelnet, telnet, Top @chapter Remote Login Interface Using SSH

This package provides support for remote logins using @code{ssh}. The package is layered on top of shell.el; the code here only accounts for the variations needed to handle a remote process, e.g. directory tracking and the sending of some special characters.

If you wish for ssh mode to prompt you in the minibuffer for passwords when a password prompt appears, just enter @code{M-x send-invisible} and type in your line, or add @code{comint-watch-for-password-prompt} to @code{comint-output-filter-functions}.

To configure this package, type:

@example
M-x customize-group RET ssh RET @end example

@node ftelnet, rlogin, ssh, Top @chapter Remote Login Interface Using Telnet

This package provides support for remote logins using @code{telnet}. The package is layered on top of shell.el; the code here only accounts for the variations needed to handle a remote process, e.g. directory tracking and the sending of some special characters.

If you wish for ftelnet mode to prompt you in the minibuffer for passwords when a password prompt appears, just enter @kbd{M-x send-invisible} and type in your line, or add @code{comint-watch-for-password-prompt} to @code{comint-output-filter-functions}.

@node rlogin, mchat, ftelnet, Top @chapter Remote Login Interface Using rlogin

This package provides support for remote logins using @code{rlogin}. The package is layered on top of shell.el; the code here only accounts for the variations needed to handle a remote process, e.g. directory tracking and the sending of some special characters.

If you wish for rlogin mode to prompt you in the minibuffer for passwords when a password prompt appears, just enter @kbd{M-x send-invisible} and type in your line, or add @code{comint-watch-for-password-prompt} to @code{comint-output-filter-functions}.

To configure this package, type:

@example
M-x customize-group RET rlogin RET @end example

@node mchat, kermit, rlogin, Top @chapter Multicast Chatting

MChat is a package allowing a conversation to take place between a potentially infinite number of people across the Internet. It uses the Multicast support that has been added to XEmacs in the early 21.0 days. At that time a rudimentary version of MChat was written, merely to illustrate the feature, and almost nobody knew it, apart from the other developers. This version is much improved and completely backwards incompatible ;-).

NOTE: before using this package, you most likely have to customize the @code{mchat-nsl-method} first. It specifies a program like @code{nsl} or @code{nslookup} in order to retrieve the IP number of your machine.

The main entry point to the package is the @code{mchat} function which allows you to open a multicast group based on the MChat protocol. There are a number a variables that can be customized and their doc-string should be self-explanatory. You might also want to look at the bindings (@kbd{C-h b}) in MChat buffers, or at the menubar entries to get an idea of what you can do.

WARNING: the current version (but there's also a limitation in the internals of XEmacs's processes) doesn't let you send messages longer than 500 octets or so, including the protocol header. I plan to change this in the future (see the todo list).

To configure this package, type:

@example
M-x customize-group RET mchat RET @end example

@node kermit, terminal, mchat, Top @chapter Using Shell Mode With Kermit

This library not documented. Please contribute!

@node terminal, spell, kermit, Top @chapter Terminal Emulator

This library not documented. Please contribute!

@node spell, background, terminal, Top @chapter Spelling Correction

This mode provides an Emacs interface to the UNIX spell(1) program. Entry points are @code{spell-buffer}, @code{spell-word}, @code{spell-region} and @code{spell-string}. These facilities are documented in the Emacs user's manual.

@node background, inf-lisp, spell, Top @chapter Fun With Background Jobs

This library not documented. Please contribute!

To configure this package, type:

@example
M-x customize-group RET background RET @end example

@node inf-lisp, ledit, background, Top @chapter Inferior-Lisp Mode

This library not documented. Please contribute!

@node ledit, XEmacs License, inf-lisp, Top @chapter ledit

This library not documented. Please contribute!

@node XEmacs License, , ledit, Top @chapter XEmacs License @unnumbered GNU GENERAL PUBLIC LICENSE @center Version 2, June 1991

@display Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc. 675 Mass Ave, Cambridge, MA 02139, USA

Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. @end display

@unnumberedsec Preamble

The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software---to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.

When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.

We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.

Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations.

Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.

The precise terms and conditions for copying, distribution and modification follow.

@iftex @unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION @end iftex @ifinfo @center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION @end ifinfo

@enumerate 0 @item This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The ``Program'', below, refers to any such program or work, and a ``work based on the Program'' means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term ``modification''.) Each licensee is addressed as ``you''.

Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.

@item You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.

You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.

@item You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:

@enumerate a @item You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change.

@item You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.

@item If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.) @end enumerate

These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

@item You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:

@enumerate a @item Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,

@item Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,

@item Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.) @end enumerate

The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.

If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.

@item You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

@item You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it.

@item Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License.

@item If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances.

It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.

This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.

@item If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.

@item The Free Software Foundation may publish revised and/or new versions of the General Public 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.

Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and ``any later version'', you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.

@item If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.

@iftex @heading NO WARRANTY @end iftex @ifinfo @center NO WARRANTY @end ifinfo

@item BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW@. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE@. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU@. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

@item IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. @end enumerate

@iftex @heading END OF TERMS AND CONDITIONS @end iftex @ifinfo @center END OF TERMS AND CONDITIONS @end ifinfo

@page @unnumberedsec How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the ``copyright'' line and a pointer to where the full notice is found.

@smallexample @var{one line to give the program's name and an idea of what it does.} Copyright (C) 19@var{yy} @var{name of author}

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., 675 Mass Ave, Cambridge, MA 02139, USA. @end smallexample

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this when it starts in an interactive mode:

@smallexample Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author} Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. @end smallexample

The hypothetical commands @samp{show w} and @samp{show c} should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than @samp{show w} and @samp{show c}; they could even be mouse-clicks or menu items---whatever suits your program.

You should also get your employer (if you work as a programmer) or your school, if any, to sign a ``copyright disclaimer'' for the program, if necessary. Here is a sample; alter the names:

@smallexample @group Yoyodyne, Inc., hereby disclaims all copyright interest in the program `Gnomovision' (which makes passes at compilers) written by James Hacker.

@var{signature of Ty Coon}, 1 April 1989 Ty Coon, President of Vice @end group @end smallexample

This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.