Info file ../info/emacs, produced by Makeinfo, -*- Text -*- from
input file emacs.tex.

This file documents the GNU Emacs editor.

Copyright (C) 1985, 1986, 1988 Richard M. Stallman.

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the sections entitled "The GNU Manifesto", "Distribution" and
"GNU General Public License" are included exactly as in the original,
and provided that the entire resulting derived work is distributed
under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that the sections entitled "The GNU Manifesto",
"Distribution" and "GNU General Public License" may be included in a
translation approved by the author instead of in the original English.

File: emacs,  Node: Bugs,  Next: Manifesto,  Prev: Lossage,  Up: Top

Reporting Bugs

  Sometimes you will encounter a bug in Emacs.  Although we cannot
promise we can or will fix the bug, and we might not even agree that
it is a bug, we want to hear about bugs you encounter in case we do
want to fix them.

  To make it possible for us to fix a bug, you must report it.  In
order to do so effectively, you must know when and how to do it.

When Is There a Bug

  If Emacs executes an illegal instruction, or dies with an operating
system error message that indicates a problem in the program (as
opposed to something like "disk full"), then it is certainly a bug.

  If Emacs updates the display in a way that does not correspond to
what is in the buffer, then it is certainly a bug.  If a command
seems to do the wrong thing but the problem corrects itself if you
type `C-l', it is a case of incorrect display updating.

  Taking forever to complete a command can be a bug, but you must make
certain that it was really Emacs's fault.  Some commands simply take
a long time.  Type `C-g' and then `C-h l' to see whether the input
Emacs received was what you intended to type; if the input was such
that you KNOW it should have been processed quickly, report a bug. 
If you don't know whether the command should take a long time, find
out by looking in the manual or by asking for assistance.

  If a command you are familiar with causes an Emacs error message in a
case where its usual definition ought to be reasonable, it is
probably a bug.

  If a command does the wrong thing, that is a bug.  But be sure you
know for certain what it ought to have done.  If you aren't familiar
with the command, or don't know for certain how the command is
supposed to work, then it might actually be working right.  Rather
than jumping to conclusions, show the problem to someone who knows
for certain.

  Finally, a command's intended definition may not be best for editing
with.  This is a very important sort of problem, but it is also a
matter of judgment.  Also, it is easy to come to such a conclusion
out of ignorance of some of the existing features.  It is probably
best not to complain about such a problem until you have checked the
documentation in the usual ways, feel confident that you understand
it, and know for certain that what you want is not available.  If you
are not sure what the command is supposed to do after a careful
reading of the manual, check the index and glossary for any terms
that may be unclear.  If you still do not understand, this indicates
a bug in the manual.  The manual's job is to make everything clear. 
It is just as important to report documentation bugs as program bugs.

  If the on-line documentation string of a function or variable
disagrees with the manual, one of them must be wrong, so report the

How to Report a Bug

  When you decide that there is a bug, it is important to report it and
to report it in a way which is useful.  What is most useful is an
exact description of what commands you type, starting with the shell
command to run Emacs, until the problem happens.  Always include the
version number of Emacs that you are using; type `M-x emacs-version'
to print this.

  The most important principle in reporting a bug is to report FACTS,
not hypotheses or categorizations.  It is always easier to report the
facts, but people seem to prefer to strain to posit explanations and
report them instead.  If the explanations are based on guesses about
how Emacs is implemented, they will be useless; we will have to try
to figure out what the facts must have been to lead to such
speculations.  Sometimes this is impossible.  But in any case, it is
unnecessary work for us.

  For example, suppose that you type `C-x C-f /glorp/baz.ugh RET',
visiting a file which (you know) happens to be rather large, and
Emacs prints out `I feel pretty today'.  The best way to report the
bug is with a sentence like the preceding one, because it gives all
the facts and nothing but the facts.

  Do not assume that the problem is due to the size of the file and
say, "When I visit a large file, Emacs prints out `I feel pretty
today'." This is what we mean by "guessing explanations".  The
problem is just as likely to be due to the fact that there is a `z'
in the file name.  If this is so, then when we got your report, we
would try out the problem with some "large file", probably with no
`z' in its name, and not find anything wrong.  There is no way in the
world that we could guess that we should try visiting a file with a
`z' in its name.

  Alternatively, the problem might be due to the fact that the file
starts with exactly 25 spaces.  For this reason, you should make sure
that you inform us of the exact contents of any file that is needed
to reproduce the bug.  What if the problem only occurs when you have
typed the `C-x C-a' command previously?  This is why we ask you to
give the exact sequence of characters you typed since starting to use

  You should not even say "visit a file" instead of `C-x C-f' unless
you know that it makes no difference which visiting command is used. 
Similarly, rather than saying "if I have three characters on the
line," say "after I type `RET A B C RET C-p'," if that is the way you
entered the text.

  If you are not in Fundamental mode when the problem occurs, you
should say what mode you are in.

  If the manifestation of the bug is an Emacs error message, it is
important to report not just the text of the error message but a
backtrace showing how the Lisp program in Emacs arrived at the error.
To make the backtrace, you must execute the Lisp expression  `(setq
debug-on-error t)' before the error happens (that is to say, you must
execute that expression and then make the bug happen).  This causes
the Lisp debugger to run (*note Lisp Debug::.).  The debugger's
backtrace can be copied as text into the bug report.  This use of the
debugger is possible only if you know how to make the bug happen
again.  Do note the error message the first time the bug happens, so
if you can't make it happen again, you can report at least that.

  Check whether any programs you have loaded into the Lisp world,
including your `.emacs' file, set any variables that may affect the
functioning of Emacs.  Also, see whether the problem happens in a
freshly started Emacs without loading your `.emacs' file (start Emacs
with the `-q' switch to prevent loading the init file.)  If the
problem does NOT occur then, it is essential that we know the
contents of any programs that you must load into the Lisp world in
order to cause the problem to occur.

  If the problem does depend on an init file or other Lisp programs
that are not part of the standard Emacs system, then you should make
sure it is not a bug in those programs by complaining to their
maintainers first.  After they verify that they are using Emacs in a
way that is supposed to work, they should report the bug.

  If you can tell us a way to cause the problem without visiting any
files, please do so.  This makes it much easier to debug.  If you do
need files, make sure you arrange for us to see their exact contents.
For example, it can often matter whether there are spaces at the ends
of lines, or a newline after the last line in the buffer (nothing
ought to care whether the last line is terminated, but tell that to
the bugs).

  The easy way to record the input to Emacs precisely is to to write a
dribble file; execute the Lisp expression

     (open-dribble-file "~/dribble")

using `Meta-ESC' or from the `*scratch*' buffer just after starting
Emacs.  From then on, all Emacs input will be written in the
specified dribble file until the Emacs process is killed.

  For possible display bugs, it is important to report the terminal
type (the value of environment variable `TERM'), the complete termcap
entry for the terminal from `/etc/termcap' (since that file is not
identical on all machines), and the output that Emacs actually sent
to the terminal.  The way to collect this output is to execute the
Lisp expression

     (open-termscript "~/termscript")

using `Meta-ESC' or from the `*scratch*' buffer just after starting
Emacs.  From then on, all output from Emacs to the terminal will be
written in the specified termscript file as well, until the Emacs
process is killed.  If the problem happens when Emacs starts up, put
this expression into your `.emacs' file so that the termscript file
will be open when Emacs displays the screen for the first time.  Be
warned: it is often difficult, and sometimes impossible, to fix a
terminal-dependent bug without access to a terminal of the type that
stimulates the bug.

  The address for reporting bugs is

GNU Emacs Bugs
545 Tech Sq, rm 703
Cambridge, MA 02139

or send email to `mit-eddie!bug-gnu-emacs' (Usenet) or
`bug-gnu-emacs@prep.ai.mit.edu' (Internet).

  Once again, we do not promise to fix the bug; but if the bug is serious,
or ugly, or easy to fix, chances are we will want to.

File: emacs,  Node: Manifesto,  Prev: Bugs,  Up: Top

The GNU Manifesto

What's GNU?  Gnu's Not Unix!

GNU, which stands for Gnu's Not Unix, is the name for the complete
Unix-compatible software system which I am writing so that I can give
it away free to everyone who can use it.  Several other volunteers
are helping me.  Contributions of time, money, programs and equipment
are greatly needed.

So far we have an Emacs text editor with Lisp for writing editor commands,
a source level debugger, a yacc-compatible parser generator, a
linker, and around 35 utilities.  A shell (command interpreter) is
nearly completed.  A new portable optimizing C compiler has compiled
itself and may be released this year.  An initial kernel exists but
many more features are needed to emulate Unix.  When the kernel and
compiler are finished, it will be possible to distribute a GNU system
suitable for program development.  We will use TeX as our text
formatter, but an nroff is being worked on.  We will use the free,
portable X window system as well.  After this we will add a portable
Common Lisp, an Empire game, a spreadsheet, and hundreds of other
things, plus on-line documentation.  We hope to supply, eventually,
everything useful that normally comes with a Unix system, and more.

GNU will be able to run Unix programs, but will not be identical to Unix. 
We will make all improvements that are convenient, based on our
experience with other operating systems.  In particular, we plan to
have longer filenames, file version numbers, a crashproof file
system, filename completion perhaps, terminal-independent display
support, and perhaps eventually a Lisp-based window system through
which several Lisp programs and ordinary Unix programs can share a
screen.  Both C and Lisp will be available as system programming
languages.  We will try to support UUCP, MIT Chaosnet, and Internet
protocols for communication.

GNU is aimed initially at machines in the 68000/16000 class with virtual
memory, because they are the easiest machines to make it run on.  The
extra effort to make it run on smaller machines will be left to
someone who wants to use it on them.

To avoid horrible confusion, please pronounce the `G' in the word `GNU'
when it is the name of this project.

Why I Must Write GNU

I consider that the golden rule requires that if I like a program I must
share it with other people who like it.  Software sellers want to
divide the users and conquer them, making each user agree not to
share with others.  I refuse to break solidarity with other users in
this way.  I cannot in good conscience sign a nondisclosure agreement
or a software license agreement.  For years I worked within the
Artificial Intelligence Lab to resist such tendencies and other
inhospitalities, but eventually they had gone too far: I could not
remain in an institution where such things are done for me against my

So that I can continue to use computers without dishonor, I have decided
to put together a sufficient body of free software so that I will be
able to get along without any software that is not free.  I have
resigned from the AI lab to deny MIT any legal excuse to prevent me
from giving GNU away.

Why GNU Will Be Compatible with Unix

Unix is not my ideal system, but it is not too bad.  The essential
features of Unix seem to be good ones, and I think I can fill in what
Unix lacks without spoiling them.  And a system compatible with Unix
would be convenient for many other people to adopt.

How GNU Will Be Available

GNU is not in the public domain.  Everyone will be permitted to modify and
redistribute GNU, but no distributor will be allowed to restrict its
further redistribution.  That is to say, proprietary modifications
will not be allowed.  I want to make sure that all versions of GNU
remain free.

Why Many Other Programmers Want to Help

I have found many other programmers who are excited about GNU and want to

Many programmers are unhappy about the commercialization of system
software.  It may enable them to make more money, but it requires
them to feel in conflict with other programmers in general rather
than feel as comrades.  The fundamental act of friendship among
programmers is the sharing of programs; marketing arrangements now
typically used essentially forbid programmers to treat others as
friends.  The purchaser of software must choose between friendship
and obeying the law.  Naturally, many decide that friendship is more
important.  But those who believe in law often do not feel at ease
with either choice.  They become cynical and think that programming
is just a way of making money.

By working on and using GNU rather than proprietary programs, we can be
hospitable to everyone and obey the law.  In addition, GNU serves as
an example to inspire and a banner to rally others to join us in
sharing.  This can give us a feeling of harmony which is impossible
if we use software that is not free.  For about half the programmers
I talk to, this is an important happiness that money cannot replace.

How You Can Contribute

I am asking computer manufacturers for donations of machines and money. 
I'm asking individuals for donations of programs and work.

One consequence you can expect if you donate machines is that GNU will run
on them at an early date.  The machines should be complete, ready to
use systems, approved for use in a residential area, and not in need
of sophisticated cooling or power.

I have found very many programmers eager to contribute part-time work for
GNU.  For most projects, such part-time distributed work would be
very hard to coordinate; the independently-written parts would not
work together.  But for the particular task of replacing Unix, this
problem is absent.  A complete Unix system contains hundreds of
utility programs, each of which is documented separately.  Most
interface specifications are fixed by Unix compatibility.  If each
contributor can write a compatible replacement for a single Unix
utility, and make it work properly in place of the original on a Unix
system, then these utilities will work right when put together.  Even
allowing for Murphy to create a few unexpected problems, assembling
these components will be a feasible task.  (The kernel will require
closer communication and will be worked on by a small, tight group.)

If I get donations of money, I may be able to hire a few people full or
part time.  The salary won't be high by programmers' standards, but
I'm looking for people for whom building community spirit is as
important as making money.  I view this as a way of enabling
dedicated people to devote their full energies to working on GNU by
sparing them the need to make a living in another way.

Why All Computer Users Will Benefit

Once GNU is written, everyone will be able to obtain good system software
free, just like air.

This means much more than just saving everyone the price of a Unix license.
It means that much wasteful duplication of system programming effort
will be avoided.  This effort can go instead into advancing the state
of the art.

Complete system sources will be available to everyone.  As a result, a
user who needs changes in the system will always be free to make them
himself, or hire any available programmer or company to make them for
him.  Users will no longer be at the mercy of one programmer or
company which owns the sources and is in sole position to make changes.

Schools will be able to provide a much more educational environment by
encouraging all students to study and improve the system code. 
Harvard's computer lab used to have the policy that no program could
be installed on the system if its sources were not on public display,
and upheld it by actually refusing to install certain programs.  I
was very much inspired by this.

Finally, the overhead of considering who owns the system software and what
one is or is not entitled to do with it will be lifted.

Arrangements to make people pay for using a program, including licensing
of copies, always incur a tremendous cost to society through the
cumbersome mechanisms necessary to figure out how much (that is,
which programs) a person must pay for.  And only a police state can
force everyone to obey them.  Consider a space station where air must
be manufactured at great cost: charging each breather per liter of
air may be fair, but wearing the metered gas mask all day and all
night is intolerable even if everyone can afford to pay the air bill.
And the TV cameras everywhere to see if you ever take the mask off
are outrageous.  It's better to support the air plant with a head tax
and chuck the masks.

Copying all or parts of a program is as natural to a programmer as
breathing, and as productive.  It ought to be as free.

Some Easily Rebutted Objections to GNU's Goals

"Nobody will use it if it is free, because that means they can't rely
on any support."

"You have to charge for the program to pay for providing the support."

If people would rather pay for GNU plus service than get GNU free without
service, a company to provide just service to people who have
obtained GNU free ought to be profitable.

We must distinguish between support in the form of real programming work
and mere handholding.  The former is something one cannot rely on
from a software vendor.  If your problem is not shared by enough
people, the vendor will tell you to get lost.

If your business needs to be able to rely on support, the only way is to
have all the necessary sources and tools.  Then you can hire any
available person to fix your problem; you are not at the mercy of any
individual.  With Unix, the price of sources puts this out of
consideration for most businesses.  With GNU this will be easy.  It
is still possible for there to be no available competent person, but
this problem cannot be blamed on distibution arrangements.  GNU does
not eliminate all the world's problems, only some of them.

Meanwhile, the users who know nothing about computers need handholding:
doing things for them which they could easily do themselves but don't
know how.

Such services could be provided by companies that sell just hand-holding
and repair service.  If it is true that users would rather spend
money and get a product with service, they will also be willing to
buy the service having got the product free.  The service companies
will compete in quality and price; users will not be tied to any
particular one.  Meanwhile, those of us who don't need the service
should be able to use the program without paying for the service.

"You cannot reach many people without advertising, and you must
charge for the program to support that."

"It's no use advertising a program people can get free."

There are various forms of free or very cheap publicity that can be used
to inform numbers of computer users about something like GNU.  But it
may be true that one can reach more microcomputer users with
advertising.  If this is really so, a business which advertises the
service of copying and mailing GNU for a fee ought to be successful
enough to pay for its advertising and more.  This way, only the users
who benefit from the advertising pay for it.

On the other hand, if many people get GNU from their friends, and such
companies don't succeed, this will show that advertising was not
really necessary to spread GNU.  Why is it that free market advocates
don't want to let the free market decide this?

"My company needs a proprietary operating system to get a competitive

GNU will remove operating system software from the realm of competition. 
You will not be able to get an edge in this area, but neither will
your competitors be able to get an edge over you.  You and they will
compete in other areas, while benefitting mutually in this one.  If
your business is selling an operating system, you will not like GNU,
but that's tough on you.  If your business is something else, GNU can
save you from being pushed into the expensive business of selling
operating systems.

I would like to see GNU development supported by gifts from many
manufacturers and users, reducing the cost to each.

"Don't programmers deserve a reward for their creativity?"

If anything deserves a reward, it is social contribution.  Creativity can
be a social contribution, but only in so far as society is free to
use the results.  If programmers deserve to be rewarded for creating
innovative programs, by the same token they deserve to be punished if
they restrict the use of these programs.

"Shouldn't a programmer be able to ask for a reward for his

There is nothing wrong with wanting pay for work, or seeking to maximize
one's income, as long as one does not use means that are destructive.
But the means customary in the field of software today are based on

Extracting money from users of a program by restricting their use of it is
destructive because the restrictions reduce the amount and the ways
that the program can be used.  This reduces the amount of wealth that
humanity derives from the program.  When there is a deliberate choice
to restrict, the harmful consequences are deliberate destruction.

The reason a good citizen does not use such destructive means to become
wealthier is that, if everyone did so, we would all become poorer
from the mutual destructiveness.  This is Kantian ethics; or, the
Golden Rule.  Since I do not like the consequences that result if
everyone hoards information, I am required to consider it wrong for
one to do so.  Specifically, the desire to be rewarded for one's
creativity does not justify depriving the world in general of all or
part of that creativity.

"Won't programmers starve?"

I could answer that nobody is forced to be a programmer.  Most of us
cannot manage to get any money for standing on the street and making
faces.  But we are not, as a result, condemned to spend our lives
standing on the street making faces, and starving.  We do something

But that is the wrong answer because it accepts the questioner's implicit
assumption: that without ownership of software, programmers cannot
possibly be paid a cent.  Supposedly it is all or nothing.

The real reason programmers will not starve is that it will still be
possible for them to get paid for programming; just not paid as much
as now.

Restricting copying is not the only basis for business in software.  It is
the most common basis because it brings in the most money.  If it
were prohibited, or rejected by the customer, software business would
move to other bases of organization which are now used less often. 
There are always numerous ways to organize any kind of business.

Probably programming will not be as lucrative on the new basis as it is
now.  But that is not an argument against the change.  It is not
considered an injustice that sales clerks make the salaries that they
now do.  If programmers made the same, that would not be an injustice
either.  (In practice they would still make considerably more than

"Don't people have a right to control how their creativity is used?"

"Control over the use of one's ideas" really constitutes control over
other people's lives; and it is usually used to make their lives more

People who have studied the issue of intellectual property rights
carefully (such as lawyers) say that there is no intrinsic right to
intellectual property.  The kinds of supposed intellectual property
rights that the government recognizes were created by specific acts
of legislation for specific purposes.

For example, the patent system was established to encourage inventors to
disclose the details of their inventions.  Its purpose was to help
society rather than to help inventors.  At the time, the life span of
17 years for a patent was short compared with the rate of advance of
the state of the art.  Since patents are an issue only among
manufacturers, for whom the cost and effort of a license agreement
are small compared with setting up production, the patents often do
not do much harm.  They do not obstruct most individuals who use
patented products.

The idea of copyright did not exist in ancient times, when authors
frequently copied other authors at length in works of non-fiction. 
This practice was useful, and is the only way many authors' works
have survived even in part.  The copyright system was created
expressly for the purpose of encouraging authorship.  In the domain
for which it was invented--books, which could be copied economically
only on a printing press--it did little harm, and did not obstruct
most of the individuals who read the books.

All intellectual property rights are just licenses granted by society
because it was thought, rightly or wrongly, that society as a whole
would benefit by granting them.  But in any particular situation, we
have to ask: are we really better off granting such license?  What
kind of act are we licensing a person to do?

The case of programs today is very different from that of books a hundred
years ago.  The fact that the easiest way to copy a program is from
one neighbor to another, the fact that a program has both source code
and object code which are distinct, and the fact that a program is
used rather than read and enjoyed, combine to create a situation in
which a person who enforces a copyright is harming society as a whole
both materially and spiritually; in which a person should not do so
regardless of whether the law enables him to.

"Competition makes things get done better."

The paradigm of competition is a race: by rewarding the winner, we
encourage everyone to run faster.  When capitalism really works this
way, it does a good job; but its defenders are wrong in assuming it
always works this way.  If the runners forget why the reward is
offered and become intent on winning, no matter how, they may find
other strategies--such as, attacking other runners.  If the runners
get into a fist fight, they will all finish late.

Proprietary and secret software is the moral equivalent of runners in a
fist fight.  Sad to say, the only referee we've got does not seem to
object to fights; he just regulates them ("For every ten yards you
run, you can fire one shot").  He really ought to break them up, and
penalize runners for even trying to fight.

"Won't everyone stop programming without a monetary incentive?"

Actually, many people will program with absolutely no monetary incentive. 
Programming has an irresistible fascination for some people, usually
the people who are best at it.  There is no shortage of professional
musicians who keep at it even though they have no hope of making a
living that way.

But really this question, though commonly asked, is not appropriate to the
situation.  Pay for programmers will not disappear, only become less.
So the right question is, will anyone program with a reduced monetary
incentive?  My experience shows that they will.

For more than ten years, many of the world's best programmers worked at
the Artificial Intelligence Lab for far less money than they could
have had anywhere else.  They got many kinds of non-monetary rewards:
fame and appreciation, for example.  And creativity is also fun, a
reward in itself.

Then most of them left when offered a chance to do the same interesting
work for a lot of money.

What the facts show is that people will program for reasons other than
riches; but if given a chance to make a lot of money as well, they
will come to expect and demand it.  Low-paying organizations do
poorly in competition with high-paying ones, but they do not have to
do badly if the high-paying ones are banned.

"We need the programmers desperately.  If they demand that we stop
helping our neighbors, we have to obey."

You're never so desperate that you have to obey this sort of demand. 
Remember: millions for defense, but not a cent for tribute!

"Programmers need to make a living somehow."

In the short run, this is true.  However, there are plenty of ways that
programmers could make a living without selling the right to use a
program.  This way is customary now because it brings programmers and
businessmen the most money, not because it is the only way to make a
living.  It is easy to find other ways if you want to find them. 
Here are a number of examples.

A manufacturer introducing a new computer will pay for the porting of
operating systems onto the new hardware.

The sale of teaching, hand-holding and maintenance services could also
employ programmers.

People with new ideas could distribute programs as freeware, asking for
donations from satisfied users, or selling hand-holding services.  I
have met people who are already working this way successfully.

Users with related needs can form users' groups, and pay dues.  A group
would contract with programming companies to write programs that the
group's members would like to use.

All sorts of development can be funded with a Software Tax:

Suppose everyone who buys a computer has to pay x percent of the
price as a software tax.  The government gives this to an agency like
the NSF to spend on software development.

But if the computer buyer makes a donation to software development
himself, he can take a credit against the tax.  He can donate to the
project of his own choosing--often, chosen because he hopes to use
the results when it is done.  He can take a credit for any amount of
donation up to the total tax he had to pay.

The total tax rate could be decided by a vote of the payers of the
tax, weighted according to the amount they will be taxed on.

The consequences:

   * The computer-using community supports software development.

   * This community decides what level of support is needed.

   * Users who care which projects their share is spent on can choose
     this for themselves.

In the long run, making programs free is a step toward the post-scarcity
world, where nobody will have to work very hard just to make a living.
People will be free to devote themselves to activities that are fun,
such as programming, after spending the necessary ten hours a week on
required tasks such as legislation, family counseling, robot repair
and asteroid prospecting.  There will be no need to be able to make a
living from programming.

We have already greatly reduced the amount of work that the whole society
must do for its actual productivity, but only a little of this has
translated itself into leisure for workers because much nonproductive
activity is required to accompany productive activity.  The main
causes of this are bureaucracy and isometric struggles against
competition.  Free software will greatly reduce these drains in the
area of software production.  We must do this, in order for technical
gains in productivity to translate into less work for us.