# Latex is really just a bunch of Tex macros?

A question of no practical importance, just curious:

One reads that Latex is just a collection of Tex macros. Is this literally true?

A more precisely specified version of the same question: Does there theoretically exist a Tex file latex.tex such that if file1.tex is a valid Latex file and file2.tex is the same as file1.tex except that it starts with the line "\input latex" then passing file2.tex to tex.exe produces the same output, eventually, as passing file1.tex to latex.exe?

• Building the LaTeX format does more-or-less exactly that (the file is called latex.ltx) ... Mar 26 '18 at 14:30
• Yep, literally true. But I don't get what you mean in the "specified version". Mar 26 '18 at 14:32
• Technically, TeX is mostly just a bunch of TeX macros. Mar 26 '18 at 14:34
• @skillmon : Means: OP turned into a real-world example, such as \input latex.ltx \documentclass{article}\begin{document}Hello World!\end{document}, processed with etex.exe. Mar 26 '18 at 14:37
• Mar 26 '18 at 14:50