Install and use latexdiff without MikTex

Question

I use overleaf on Windows for my research papers and thesis and it works fine. However, I received reviews from a journal, and they require me to track changes in my old and final manuscript. Inspire by this answer, I decided to use latexdiff but it isn't working. I installed Perl v5.28.1 (I think it installed correctly because Perl -v returns the version), and downloaded latexdiff from here. I extracted and copied the files to C:\Perl64\bin as described here. Now, if I attempt to run the command in CMD, I get the following error:

'latexdiff' is not recognized as an internal or external command, operable program or batch file.

I have two questions.

1. Why am I getting this error?

2. The tutorials I found on YouTube all work with MikTex, but I want to stick to overleaf. How do you use latexdiff without having to install latex in your system?

Answer 1

As an alternative to running latexdiff locally and copying the file back to Overleaf you can run latexdiff at overleaf.

Here is a project with two versions of a tex file and a displayed diff

It is currently live on Overleaf but this link may not be good forever, but I show the files inline below.

https://www.overleaf.com/read/xhszmytdmqqg

main.tex (the old version)

\documentclass{article}


\title{ld}
\author{me}
\date{July 2021}

\begin{document}

\maketitle

\section{Introduction}
zzz
\end{document}

main2.tex (new version)

\documentclass{article}


\title{latexdiff}
\author{me\and you}
\date{July 2021}

\begin{document}

\maketitle

\section{Introduction}
zzz zzz

\section{Section}
zzz
\end{document}

latexmkrc (to instruct overleaf to show the diff)

$pdflatex = "latexdiff main.tex main2.tex > main-d.tex; pdflatex %O  main-d"

When you want to see the "normal" typeset version of main.tex without the diff marking, just add a # comment marker to the latexmkrc setting so it looks like

# $pdflatex = "latexdiff main.tex main2.tex > main-d.tex; pdflatex %O  main-d"

then recompiling main.tex or main2.tex will produce the normal typeset output.

Answer 2

(Tom from Overleaf Support here.)

An alternative way to what David proposes is by using ShellEscape to run latexdiff. You can simply create a new file called e.g. diff.tex with the following contents:

\RequirePackage{shellesc}
\ShellEscape{latexdiff main.tex main2.tex > diff_result.tex}
\input{diff_result}
\documentclass{dummy}

If you Recompile with this file open in the editor, it will show a diff-ed PDF. If you Recompile with any of main.tex or main2.tex open, it will show the corresponding non-diff-ed document.

(Note that the line \documentclass{dummy} is necessary to trick Overleaf's compiler into believing this file is compilable. The compiler checks for \documentclass and if it doesn't find it, it compiles the Main file as chosen in the Menu; however, when it does fine it, it considers the current file to be main.)

In Overleaf, you can get the previous version of the file from the project's History, you can simply download the project at an earlier version, extract the file from it and upload it (under a different name) back to the project.