.TH TEX 1 "13 May 92"
.SH NAME
tex, virtex  \- text formatting and typesetting
.SH SYNOPSIS
.B tex
[ first line ]
.PP
.B initex
[ first line ]
.PP
.B virtex
[ first line ]
.ie t .ds TX \fRT\v'+0.25m'E\v'-0.25m'X\fP\" for troff
.el .ds TX TeX\" for nroff
.\" to use, type \*(TX
.ie t .ds OX \fIT\v'+0.25m'E\v'-0.25m'X\fP\" for troff
.el .ds OX TeX\" for nroff
.\" the same but obliqued
.SH DESCRIPTION
\*(TX
formats the interspersed text and commands contained in the named
files
and outputs a typesetter independent file (called
.I DVI
which is short for
.IR D e V ice
.IR I "ndependent )."
\*(TX
capabilities and language are described in
.I The \*(OXbook
by Donald E. Knuth, published by Addison-Wesley.
.PP
\*(TX
is normally used with a large body of precompiled macros,
and there are several specific formatting systems, such as
LaTeX, 
which require the support of several macro files.  The basic
programs as compiled are called
.I initex
and
.I virtex, 
and are distinguished by the fact that 
.I initex 
can be used to precompile macros into a 
.I .fmt
file,
which is used by
.IR virtex .
On the other hand,
.I virtex
starts more quickly and can read a precompiled 
.I .fmt
file, but it cannot create one.  It is the version of
\*(TX
which is usually invoked in production, as opposed to installation.
.PP
Any arguments given on the command line to the
\*(TX
programs are passed to them as the first input line.
(But it is often easier to type extended arguments
as the first input line, since shells tend
to gobble up or misinterpret \*(TX's favorite symbols, like backslashes,
unless you quote them.)
As described in 
.I The \*(OXbook,
that first line should begin with a file name
or a \\controlsequence.
The normal usage is to say
.RB `` tex
.IR paper ''
to start processing 
.I paper\|.\|tex.
The name ``paper'' will be the ``jobname'', and is used in forming
output file names.
If \*(TX doesn't get a file name in the first line, the jobname is ``texput''.
The default extension, 
.IR .tex ,
can be overridden by specifying an extension explicitly.
.PP
If there is no paper\|.\|tex in the current directory, \*(TX will
look through a search path of directories to try to find it.
If ``paper'' is the ``jobname''
a log of error messages, with rather more detail than
normally appears on the screen, will appear in 
.I paper\|.\|log,
and the output file will be in
.I paper\|.\|dvi.
The system library
.B /usr/local/lib/tex/macros
contains the basic macro package
.I plain\|.\|tex, 
described in 
.I The \*(OXbook, 
as well as several others.
Except when \fI.\|fmt\fP files are being prepared
it is hardly ever necessary to \\input plain, since almost
all instances of \*(TX begin by loading 
.IR plain.fmt .
This means that all of the control sequences discussed in 
.I "The \*(OXbook"
are known when you invoke
.IR tex .
For a discussion of \fI.\|fmt\fP files, see below.
.PP
Several environment variables can be used to set up directory
paths to search when \*(TX opens a file for input.
For example, the
.I csh
command
.br
.in +4
setenv \s-2TEXINPUTS\s0 .\|:\|/usr/me/mylib:/usr/local/lib/tex/macros
.in -4
or the
.I sh
command sequence
.br
.in +4
\s-2TEXINPUTS\s0=.\|:\|/usr/me/mylib:
.br
export \s-2TEXINPUTS\s0
.in -4
.br
would cause all invocations of \*(TX and its derivatives to look for
\\input files first in the current directory, then in a hypothetical
user's ``mylib'', and finally in the system library.  (\*(TX expands a
trailing or leading colon into the system directories.)
Normally, you would place the variable assignment which sets up the
\s-2TEXINPUTS\s0 environment variable in your
.I .login
or
.I .profile
file.
The environment variables
section below lists the relevant environment variables,
and their defaults.
.PP
The
.I e
response to \*(TX's error prompt causes the
system default
editor to start up at the current line of the current file.
There is an environment variable, \s-2TEXEDIT\s0, that can be used to change the
editor used.  It should contain a string with "%s" indicating where the
filename goes and "%d" indicating where the decimal linenumber (if any) goes.
For example, a \s-2TEXEDIT\s0 string for
.I vi
can be set with the
.I csh
command
.br
.ti +4
setenv \s-2TEXEDIT\s0 "/usr/ucb/vi +%d %s"
.br
.PP
A convenient file in the library is
.IR null.tex ,
containing nothing.
When \*(TX can't find a file it thinks you want to input, it keeps
asking you for another file name;  responding `null' gets you out
of the loop if you don't want to input anything.  You can also type your
EOF character (usually control-D).
.PP
The
.I initex
and
.IR virtex 
programs
can be used to create fast-loading versions of \*(TX 
based on macro source files.
The
.I initex
program is used to create a
.I format (.\|fmt)
file that permits fast loading of fonts and macro packages.
After processing the fonts and definitions desired, a \\dump command
will create the format file.
The format file is used by
.I virtex.
It needs to be given a format file name as the first thing it reads.
A format file name is preceded by an &, which needs to be escaped with
\\ to prevent misinterpretation by your shell
if given on the command line.
.PP
Fortunately, it is no longer necessary to make explicit references
to the format file.  The present version of \*(TX, when compiled
from this distribution, looks at its own command line to determine
what name it was called under.  It then uses that name, with the
``.\|fmt'' suffix appended, to search for the appropriate format file.
During installation,  one format file with the name
.I tex\|.\|fmt,
with only the 
.I plain\|.\|tex 
macros defined, should have been created.
This will be your format file when
you invoke \fIvirtex\fP with the name \fItex\fP.
You can also create a file
.I mytex.fmt
using \fIinitex\fP,
so that this will be loaded when you invoke 
\fIvirtex\fP with the name \fImytex\fP.
To make the whole thing work, it is necessary to link \fIvirtex\fP to all
the names of format files that you have prepared.  Hard links will do
for system-wide equivalences and Unix systems which do
not use symbolic links.  Symbolic links can be used for access 
to formats for individual projects.  For example: 
\fIvirtex\fP can be hard linked to \fItex\fP in the
general system directory for executable programs, but
an individual version of \*(TX will more likely be
linked by a symbolic link in a privately maintained path
.br
.ti +4
ln \-s /usr/local/bin/virtex mytex
.br
in a directory such as \fI/home/me/bin\fP.
.PP
Another approach is to
set up a alias using, for example, the C shell:
.br
.ti +4
alias mytex virtex \\&myfmt
.br
Besides being more cumbersome, however, this approach is
not available to systems which do not accept aliases.
Finally, there is the system known as ``undump'' which
takes the headers from an \fIa.out\fP file (e.g. \fIvirtex\fP)
and applies them to a core image which has been dumped
by the Unix \s-2QUIT\s0 signal.  This is very system-dependent,
and produces extremely large files when used with a large-memory
version of \*(TX.  This can produce executables which load faster, but
the executables also consume enormous amounts of disk space.
.SH ENVIRONMENT
The defaults for all environment variables are set at the
time of compilation in a file named
.I site.h 
in the web2c distribution.  All paths are colon-separated. 
If you set an environment variable to a value that has a leading colon,
the system default shown here is prepended.  Likewise for a trailing
colon.  For example, if you say
.br
.ti +4
setenv TEXFONTS /u/karl/myfonts:
.br
\*(TX will search
.br
.ti +4
/u/karl/myfonts:/usr/local/lib/tex/fonts/tfm:..
.PP
If one of the components in a search path ends with two slashes, e.g.,
.br
.ti +4
:/u/karl/myfonts//.
.br
then all subdirectories of the given path are searched, instead of the
directory itself.  For efficiency reasons, however, if a directory being
searched for subdirectories contains only symbolic links (to
directories), and no real subdirectories, the symbolic links are not
followed.  You can work around this by simply creating a dummy
subdirectory.  Perhaps this limitation will be removed in the future.
.PP
A ~ character at the beginning of a path component, as in
.ti +4
~:/system/dir//
.br
expands into the current home directory.  ~user expands into user's home
directory.  In most \*(TX formats, however, you cannot use ~ in a
filename you give directly to \*(TX, because ~ is an active character,
and hence is expanded, not taken as part of the filename.  Other
programs, such as Metafont, do not have this problem.
.PP
All the programs in the base \*(TX
distribution use this same search method.
.PP
Normally, \*(TX puts its output files in the current directory.  If
any output file cannot be opened there, it tries to open it in the
directory specified in the environment variable \s-2TEXMFOUTPUT\s0. 
There is no default value for that variable.  For example, if you say
.BR "tex paper"
and the current directory is not writable, and \s-2TEXMFOUTPUT\s0 has
the value
.BR /tmp ,
\*(TX attempts to create
.B /tmp/paper.log
(and 
.BR /tmp/paper.dvi ,
if any output is produced.)
.PP
.IP \s-2TEXINPUTS\s0
Search path for \\input and \\openin files.
This should probably start with ``.''.
Default: 
.BR .:/usr/local/lib/tex/macros .
.IP \s-2TEXFONTS\s0
Search path for font metric (.tfm) files.
Default: 
.BR /usr/local/lib/tex/fonts/tfm:. .
.IP \s-2TEXFORMATS\s0
Search path for format files.  Default: 
.BR /usr/local/lib/tex/formats .
.IP \s-2TEXPOOL\s0
Search path for \s-2INITEX\s0 internal strings.  Default: 
.BR /usr/local/lib/tex .
.IP \s-2TEXEDIT\s0
Command template for switching to editor.  Default: 
.BR "/usr/bin/vi +%d %s" .
.SH FILES
.TP 2i
/usr/local/lib/tex
\*(TX's library areas
.TP
/usr/local/lib/tex/tex.pool
Encoded text of \*(TX's messages.
.TP
/usr/local/lib/tex/fonts/*.tfm
Metric files for \*(TX's fonts.
.TP
/usr/local/lib/tex/fonts/*\fInnn\fP{gf,pk}
Bitmaps for various devices.  These files are not used by \*(TX.
.TP
/usr/local/lib/tex/formats/*\|.\|fmt
\*(TX .\|fmt files.
.TP
/usr/local/lib/tex/macros/plain\|.\|tex
The ``default'' macro package.
.br
.SH "SEE ALSO"
Donald E. Knuth,
.I The \*(OXbook
.br
Leslie Lamport,
.I The LaTeX  Document Preparation System
.br
Michael Spivak,
.I The Joy of \*(TX
.br
.I TUGBOAT
(the publication of the \*(TX Users Group)
.SH TRIVIA
\*(TX, pronounced properly, rhymes with ``blecchhh.''  Note that the proper
spelling in typewriter-like media is ``TeX'' and not ``TEX'' or ``tex.''
.SH AUTHORS
\*(TX was designed by Donald E. Knuth, 
who implemented it using his W\s-2EB\s0 system for Pascal programs.
It was ported to Unix at Stanford by Howard Trickey, and
at Cornell by Pavel Curtis.
The version now offered with the Unix \*(TX distribution is that 
generated by the W\s-2EB\s0 to C system, written by Tom
Rokicki and Tim Morgan.