Mathematica snippet to mass-export to pdf all notebooks in a directory.

gistfile1.mathematica

myPrintNotebook[filename_String] := Block[{nbo, pdfnamne},
  nbo = NotebookOpen[ToFileName[Directory[], filename], 
    Visible -> False];
  FrontEndExecute[FrontEndToken[nbo, "SelectAll"]];
  FrontEndTokenExecute[nbo, "SelectionOpenAllGroups"];
  pdfname = StringReplace[filename, ".nb" -> "_nb.pdf"];
  Export[pdfname, nbo, "PDF"];
  Print["saving to ", pdfname];
  NotebookClose[nbo];
]