To Err is Human

Abstract

To recapitulate on the use of LATEX, the reader may recall that we type our text containing the formatting commands in an input file using our favorite editor. We then invoke the TEX typesetting program, which processes the input file using the LATEX format, outputting a minimum of three files: a DVI file, an auxiliary file used by the program to generate things such as cross-references, and a log file that contains information about what TEX encountered, including details of any warnings or errors. While it is typesetting a file, TEX tells you about its progress either in a window or, on older systems, on the full screen of your computer. Any warnings are described without the program halting, and on faster systems some of this can be rather fleeting, but since they are reproduced in the log file, this can be examined afterwards. When an error is encountered, the program actually halts, giving an indication of the nature of the error, on which line of your input file the error might be found, and a? prompt. Warning messages indicate problems that are not serious but that are likely to affect the output (e.g., problems with hyphenation, line-breaking, cross-references and labels, finding a particular font, etc.), while errors are more serious, causing the TEX program to stop (e.g., the messages environment undefined, an omitted item in a list making environment, and misplaced alignment tab character &, among others).