L^ATEX under OS/2 and DOS

The only special problems in using L^ATEX caused by OS/2 and DOS involve the way files are handled. The first problem arises because, when a program starts to write a file, the previous version of that file is destroyed. Thus, if an error forces you to stop L^ATEX prematurely (by typing Control-C), then the files that L^ATEX was writing are incomplete, and the previous complete versions have been destroyed. You probably don't care about the output on the dvi file, but, if you are making a table of contents or using cross-referencing commands, then L^ATEX also writes one or more auxiliary files that it reads the next time it processes the same input file. If the auxiliary files are incomplete because L^ATEX was stopped before reaching the end of its input file, then the table of contents and cross-references will be incorrect the next time L^ATEX is run on the same input file. You will have to run L^ATEX a second time to get them right. If you want to avoid having to run L^ATEX twice after making an error—for example, if your input is very long—then you should save copies of these auxiliary files before running L^ATEX. An input file named myfile.tex and all the auxiliary files produced by L^ATEX from it are included in the file specification myfile.*. Use the copy command to save copies of these files.

The second problem in using L^ATEX on OS/2 and DOS involves the files that L^ATEX reads. The file whose name you type with the latex command is called the root file. In addition to reading the root file, L^ATEX also reads the files specified by \input and \include commands. With the OS/2 and DOS directory systems, L^ATEX must know not only the names of these file but also on what directories they are. It will have no problem finding the correct files if you follow two simple rules:

1. Run L^ATEX from the directory containing the root file.
2. Keep all files specified by \input and \include commands in the same directory as the root file.

You should never break the first rule, otherwise L^ATEX will have trouble finding auxiliary files. (To run L^ATEX on someone else's file, copy the file to your directory.) If you break the second rule, specifying a file from another directory in an \input or \include command, you must use a complete path name. For example, to include the file hisfile.tex from the directory \foo\bar on drive D, you can type

     \include{d:/foo/bar/hisfile}

For people who don't like to obey rules, here is exactly how L^ATEX finds its files. The root file and all files specified in the L^ATEX input, including document-style (sty) files specified by the \documentstyle command, are read from the current directory (or the specified drive/directory if the file specification includes a drive and/or a path).

L^ATEX's auxiliary files are read and written in the directory from which it is run (current directory). If L^ATEX does not find a file starting in this directory, it searches all directories listed in the TEXINPUT environment variable. As a last resort, L^ATEX tries to find the file in the \emtex\texinput directory of the current drive. You can change the directories in which L^ATEX looks for its input files by setting the environment variable TEXINPUT. Putting the command

     set TEXINPUT=d:\mytex;d:\texinput