#pdflatex introduction.tex
pdflatex introduction.tex
pgrep -f "xpdf -remote 127.0.0.1 introduction.pdf" 2>&1 > /dev/null
if [ $? == 0 ]; then
  xpdf -remote 127.0.0.1 -reload -raise
else
  xpdf -remote 127.0.0.1 introduction.pdf &
fi