makefile for latex compiling

makefile

LATEX=pdflatex
LATEXOPT=--shell-escape
NONSTOP=--interaction=batchmode#--interaction=nonstopmode

LATEXMK=latexmk
LATEXMKOPT=-pdf

MAIN=main

all: clean
	$(LATEXMK) $(LATEXMKOPT) $(NONSTOP) -pdflatex="$(LATEX) $(LATEXOPT) %O %S" $(MAIN)
	make clean
	make split

clean:
	$(LATEXMK) --c $(MAIN)
	rm -rf *~ *.tmp

split:
	pdftk $(MAIN).pdf cat 1-13 output core.pdf
	pdftk $(MAIN).pdf cat 14-r1 output supplementary.pdf

.PHONY: all clean

What does NONSTOP=--interaction=batchmode#--interaction=nonstopmode do?

PS I usually use a much simpler Makefile, texi2pdf does the entire latex/bibtex/latex dance for you, and --tidy puts all the aux files in a separate subfolder main.t2d

main :
	texi2pdf --shell-escape --tidy main.tex

clean :
	rm -rf main.t2d
	make