How to iterate through the name of files in a folder

Question

Assume I have many TeX files. For the sake of simplicity, also asssume they are in a single folder or directory.

I want to input all files from within my main LaTeX document. Actually I can create a list of those files using C# in advance.

To enrich my view about LaTeX or TeX, could you tell me whether or not this job can be done only by using pure TeX or LaTeX?

Answer 1

\documentclass{article}
\makeatletter
\def\app@exe{\immediate\write18}
\def\inputAllFiles#1{%
  \app@exe{ls #1/*.txt | xargs cat >> #1/\jobname.tmp}%
  \InputIfFileExists{#1/\jobname.tmp}{}{}
  \AtEndDocument{\app@exe{rm -f #1/\jobname.tmp}}}
\makeatother
\begin{document}

\inputAllFiles{.}% from the current dir 

\end{document}

Not really difficult. It is only an appetizer of how it can be done. This one only reads files *.txt. You have to run it with pdflatex -shell-escape test

Answer 2

If there is some sort of naming convention that is used for the files than this can be done as in Can i automatically load chapters and sections based on the filesystem?

\documentclass{article}

\newcommand*{\MaxNumOfChapters}{10}% Adjust these two settings for your needs.
\newcommand*{\MaxNumOfSections}{6}%

\usepackage{pgffor}%

\begin{document}
\foreach \c in {1,2,...,\MaxNumOfChapters}{%
    \foreach \s in {1,2,...,\MaxNumOfSections}{%
        \IfFileExists{Chapter\c/Section\s} {%
            \input{Chapter\c/Section\s}%
        }{%
                % files does not exist, so nothing to do
        }%
    }%
}%
\end{document}

This assumes that there is a directory for each chapter named Chapter<i> directory contains files named Section<n>. Should be able to customize this depending on your specific case.

This should work across different operating systems.

If there is not specfic naming convention, you can adjust this to process a list of files generated by your C# program. For example, if the C# program can generate ListOfFiles.tex as

\newcommand*{\ListOfFiles}{%
    Chapter1/Section1,
    Chapter1/Section2,
    Chapter1/Section3,
    Chapter2/Section1,
    Chapter2/Section2
}%

then you can process this as:

\documentclass{article}%
\usepackage{pgffor}%

\input{ListOfFiles}%

\begin{document}%
\foreach \c in \ListOfFiles {%
    \input{\c}%
}%
\end{document}

Answer 3

A LuaTeX solution:

the TeX driver:

\directlua{dofile("inputall.lua")}

\bye

and the Lua input file inputall.lua:

function dirtree(dir)

  if string.sub(dir, -1) == "/" then
    dir=string.sub(dir, 1, -2)
  end

  local function yieldtree(dir)
    for entry in lfs.dir(dir) do
      if not entry:match("^%.") then
        entry=dir.."/"..entry
          if lfs.isdir(entry) then
            yieldtree(entry)
          else
            coroutine.yield(entry)
          end
      end
    end
  end

  return coroutine.wrap(function() yieldtree(dir) end)
end


for i in dirtree(lfs.currentdir()) do
  local filename = i:gsub(".*/([^/]+)$","%1")
  tex.sprint("\\input " ..  filename .. " ")
end

This recurses down a directory tree and inputs all the file found. (Found the dirtree iterator in the Lua users wiki.)

Answer 4

I don't know whether you can; you probably can't, and if you could, the facilities for it are almost certainly extremely limited and likely based on \write18, which makes the OS do all the work anyway. However, I don't think you should, since it is far from being a typesetting task, which is the only kind of job TeX is designed to do. Consider:

• If all you want is a list of \input{filename.tex}'s, and if you can already programmatically create a list of filenames using some other language, then you can also generate a TeX file (or file fragment) using that language.

• I don't know how you created these files, but if you did it by hand, then perhaps you gave them meaningful names, like introduction.tex, body.tex, and conclusion.tex. No form of automatic sorting will give you the right order, so you're back to creating a list by some other means, for which see the previous point.

• How many times are you going to TeX this document? If only once, you may as well just write the names in by hand and concentrate on your writing and/or other TeX coding which it contains.

Basically, this is a bookkeeping task which doesn't depend on anything within a TeX document, and therefore is better done by one of the many scripting languages which support filesystem interaction (not to mention programming in general) to a far greater extent than TeX itself.

Answer 5

Here's a simpler Luatex solution

function inputAll(dir)
    for file in lfs.dir(dir) do
        fullpath = dir .."/".. file
        modeAttr = lfs.attributes(fullpath, "mode")
        extension = string.sub(file,#file-3,#file)
        if modeAttr == "file" and extension == ".tex" then
            tex.sprint("\\input{" .. fullpath .. "}")
        end
    end
end

Call using something like

\directlua{
  dofile("scripts/inputall.lua");
  inputAll("Skills")
}

Answer 6

Here's a platform independent approach (although it requires Java) using texosquery.

\documentclass{article}

\usepackage{texosquery}

\begin{document}
% Find all files matching the (anchored) regular expression .+\.c
% in the current directory and store the result in a comma-separated
% list in the command \result
\TeXOSQueryFilterFileList{\result}{,}{.+\string\.c}{.}

\ifx\result\empty
 Query failed!
\else
 \makeatletter
 \@for\thisfile:=\result\do{File: \thisfile. }
 \makeatother
\fi
\end{document}

If you have Java 8 and texosquery-jre8 is on the restricted list (which it is for TeX Live 2017 onwards), then change the texosquery.cfg file to include:

\def\TeXOSInvokerName{texosquery-jre8}

and uncomment

\TeXOSQueryAllowRestricted

(MiKTeX users additionally need to enable piped-shell escape support.) Once this has been set up then texosquery-jre8 can be run in restricted mode, which is safer than using -shell-escape.

There are variations of \TeXOSQueryFilterFileList, such as \TeXOSQueryFilterFileListDateAsc to order by date etc.