qpdf

• project on github: qpdf: qpdf: A content-preserving PDF document transformer
• see also exiftool

install qpdf

brew install qpdf

remove metadata from pdf

if in doubt, consider using dangerzone

qpdf --linearize --replace-input foobar.pdf

as part of an (zsh) alias:

function qpdfclean() {
  emulate -L zsh
  local f
  for f in "$@"; do
    qpdf --linearize --replace-input -- "$f"
  done
}