Using a batch script in latex \immediate\write18 env

Question

I am trying to write a script that using texcount will output only the number of characters including spaces. I made a batch script which works, no problems there.

The problem is trying to run it in latex shell escape in overleaf using the \immediate\write18 environment. The problems seems mostly to be with how latex handles the special characters used in the batchscript. The script/latex code is as follows:

\newcommand{\quickcharcount}[1]{%
\immediate\write18{
texcount -1 -sum -merge -char -q main.tex > chars.txt
texcount -1 -sum -merge -q main.tex > spaces.txt
for /f "skip=1" %%G IN (spaces.txt) DO if not defined line set "nSpace=%%G"
for /f "skip=1" %%G IN (chars.txt) DO if not defined line set "nChar=%%G"
for /f "tokens=1*delims=:" %%G in ('findstr /n "^" spaces.txt') do if %%G equ 2 set "nSpace=%%H"
for /f "tokens=1*delims=:" %%G in ('findstr /n "^" chars.txt') do if %%G equ 2 set "nChar=%%H"
set /a "sum=nChar+nSpace"
echo %sum% > count.sum
}%
\input{count.sum} 
}

Does anyone have experience with this, and know how to solve the problem?

EDIT:

I was told it was not possible with a bat script, so I have now written it as a shell script. But I am still struggling with getting it to work inside latex. You said it was somewhat restrictive with overleaf, so could this also be the reason here?

#!/bin/bash
char=$(texcount -1 -sum -merge -char -q main.tex)
space=$(texcount -1 -sum -merge -q main.tex)
nChar=${char%(*}
nSpace=${space%(*}
sum=$((nChar + nSpace))
echo $sum > count.sum

Answer 1

You have defined \quickcharcount to have 1 argument you don't use so I defined it with no arguments.

A newline in the source is a space so all your script is on one line. You could use ^^J to write a newline but here I just use the bash command separator ; You also need \@percentchar as % is a comment.

\documentclass{article}
\makeatletter
\newcommand{\quickcharcount}{%no argument
\immediate\write18{
char=$(texcount -1 -sum -merge -char -q main.tex);
space=$(texcount -1 -sum -merge -q main.tex);
nChar=${char@percentchar(};
nSpace=${space@percentchar(};
sum=$((nChar + nSpace));
echo $sum > count.sum
}%
\input{count.sum}%
}
\makeatother
\begin{document}
abc xyz
\quickcharcount
\end{document}