.tex File — LaTeX Source Document

TEX files contain source code written in the LaTeX typesetting system, which is built on Donald Knuth's TeX typesetting engine created in 1978. LaTeX uses markup commands to describe document structure, mathematical equations, cross-references, bibliographies, and formatting. It produces publication-quality output, particularly for documents with complex mathematical notation, making it the standard in academia for scientific papers, theses, and technical documentation. TEX files are plain text that can be compiled into PDF, DVI, or PostScript output using tools like pdflatex, xelatex, or lualatex. The format supports packages that extend functionality for diagrams, code listings, chemical formulas, musical notation, and more through the Comprehensive TeX Archive Network (CTAN). LaTeX enforces logical document structure through commands like section, chapter, and figure, encouraging authors to focus on content rather than visual formatting. The ecosystem includes BibTeX for bibliography management and specialized document classes for journals and institutions.