xxxxxxxxxx
# Fast way, will popup the browser probably
xdg-open file.pdf
# Gnome-way will popup default reader (actually works with any file)
gio open file.pdf
xxxxxxxxxx
# try less, it may have pdftotext
less file.pdf
# or conver it manually
pdftotext filname.pdf - | less
# for pictures convert to html:
pdftohtml -i file.pdf | xdg-open file.html