Macro for promoting sections to chapters

Question

I have a document where I would like to "promote" all sections to chapters, all subsections to sections, etc. That should affect not only the table of contents, but the documents as a whole.

For example:

\section{Title A}
\subsection{Title B}
\subsubsection{Title C}

Should actually be treated as if the document was like this:

\chapter{Title A}
\section{Title B}
\subsection{Title C}

I searched in this website how to do it, but most of the answers seem to focus on the table of contents. I tried to do it myself by adding the following to my document:

\renewcommand{\section}[1]{\chapter{#1}}
\renewcommand{\subsection}[1]{\section{#1}}
\renewcommand{\subsubsection}[1]{\subsection{#1}}

However what I get with that is that everything becomes a chapter, as if it is applied recursively. So the result is as if the document was like this:

\chapter{Title A}
\chapter{Title B}
\chapter{Title C}

Does anyone have an idea of how I can get what I need with minimal changes to the original tex files (possibly none, since it is a huge document with many sections)?

Thank you!

Answer 1

One option:

\documentclass{book}

\let\subparagraph\paragraph
\let\paragraph\subsubsection
\let\subsubsection\subsection
\let\subsection\section
\let\section\chapter

\begin{document}

\tableofcontents
\section{Test section to chapter}
\subsection{Test subsection to section}
\subsubsection{Test subsubsection to subsection}
\paragraph{Test paragraph to subsubsection}
\subparagraph{Test subparagraph to paragraph}

\end{document}

An image of the document with the \let lines commented out:

An image of the same document with the \let lines active:

The ToC:

and the first page of the body:

Answer 2

If you mean you want to make this action nearly automatic, you could use the C-c = option in reftex with the AUCTeX package. From there, use > or < to promote or demote the relevant portion of the document. This brings with it the sub-portions of those documents.