first redhat normally dose not use "sudo" that is unless it is set up by the system admin
" su " and " su - " are the default
so did you do a search ? for the correct name
Code:
su -
yum search poppler
the list will include things like
" libpoppler-devel "
" libpoppler-glib-devel "
" libpoppler-qt4-devel "