MainTex

MainTex refers to the primary TeX or LaTeX source file that serves as the entry point for compiling a document. It defines the document class, loads required packages, sets global parameters, and contains the document content or references to other files.

In multi-file projects, the MainTex file often uses commands such as \input or \include to bring in additional chapters, sections, or other content. It may also specify \includeonly to limit compilation to selected parts. The MainTex file typically includes the document environment, with the content structured into chapters or sections, potentially stored in separate files that are included from the main file.

Editors and build tools may designate a root or master document—the file considered the main file for compilation. This file is commonly named main.tex or root.tex, but any .tex file can serve as the main file as long as it is configured as the entry point in the build workflow. The MainTex file is then compiled by a TeX engine such as pdflatex, xelatex, or lualatex, often in conjunction with bibliography processors like BibTeX or biber and index tools like makeindex.

Best practices include placing global settings in the preamble, keeping the MainTex file concise, and organizing content into modular files that are included from the main file. In certain workflows, the MainTex file is the only file that editors attempt to build, while other sources are required by separate commands or packages. Understanding the role of the MainTex file helps in managing large documents and ensuring reproducible builds.