virtex [ first line ]
is normally used with a large body of precompiled macros, and there are several specific formatting systems, such as , which require the support of several macro files. The basic programs as compiled are called initex and virtex , and are distinguished by the fact that initex can be used to precompile macros into a .fmt file, which is used by virtex . On the other hand, virtex starts more quickly and can read a precompiled .fmt file, but it cannot create one. It is the version of which is usually invoked in production, as opposed to installation.
Any arguments given on the command line to the 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 UNIX shells tend to gobble up or misinterpret 's favorite symbols, like backslashes, unless you quote them.) As described in The book , that first line should begin with a filename or a \controlsequence. The normal usage is to say
If there is no paper.tex in the current directory, 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 paper.log, and the output file will be in paper.dvi. The system library directory /usr/local/lib/tex/macros contains the basic macro package plain.tex, described in The book , as well as several others. Except when .fmt files are being prepared it is unnecessary to \input plain , since almost all instances of begin by loading plain.fmt . This means that all of the control sequences discussed in The book are known when you invoke tex . For a discussion of .fmt files, see below.
The e response to 's error prompt causes the system default editor to start up at the current line of the current file. The environment variable TEXEDIT can be used to change the editor used. It can contain a string with "%s" indicating where the filename goes and "%d" indicating where the decimal line number (if any) goes. For example, a TEXEDIT string for vi can be set with the csh command
The initex and virtex programs can be used to create fast-loading versions of based on macro source files. The initex program is used to create a 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 virtex . It needs to be given a format filename as the first thing it reads. A format filename is preceded by an &, which needs to be escaped with \, or quoted, to prevent misinterpretation by the UNIX shell if given on the command line.
Fortunately, it is no longer necessary to make explicit references to the format file. The present version of , 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 tex.fmt, with only the plain.tex macros defined, should have been created. This will be your format file when you invoke virtex with the name tex . You can also create a file mytex.fmt using initex , so that this will be loaded when you invoke virtex with the name mytex . To make the whole thing work, it is necessary to link virtex 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: virtex can be hard linked to tex in the general system directory for executable programs, but an individual version of will more likely be linked to a private version by a symbolic link:
Another approach is to set up an alias using, for example, csh (1):
When looking for a font f , (and its companion programs) first look for a file starting with f in the various font directories (see the next section). If no such file is found, it then looks for a file texfonts.map in each of the font directories in turn. Each non-blank non-comment line of texfonts.map specifies mappings from one name to another. (Comments start with % and continue to the end of the line.) The target name is the first word (words are separated by spaces or tabs) and the source name is the second. (Subsequent words are ignored, so that information intended for other programs can be given there.) Thus, going back to f for a moment, if reads a texfonts.map entry that looks like g f it will then search for a font file starting with g .
A ~ character at the beginning of a path component, as in
All the programs in the web2c distribution (as well as some others) use this same search method.
Normally, 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 TEXMFOUTPUT. There is no default value for that variable. For example, if you say tex paper and the current directory is not writable, if TEXMFOUTPUT has the value /tmp , attempts to create /tmp/paper.log (and /tmp/paper.dvi , if any output is produced.)