diff --git a/cpdf.ml b/cpdf.ml
index e8c5d36..68f3ec8 100644
--- a/cpdf.ml
+++ b/cpdf.ml
@@ -70,7 +70,7 @@ let find_cpdflin provided =
 of the cpdflin binary. Returns the exit code. *)
 let call_cpdflin cpdflin temp output best_password =
   let command =
-    cpdflin ^ " --linearize " ^ " --password=" ^ best_password ^ " " ^
+    Filename.quote cpdflin ^ " --linearize " ^ " --password=" ^ best_password ^ " " ^
     Filename.quote temp ^ " " ^ Filename.quote output 
   in
     match Sys.os_type with
@@ -87,8 +87,8 @@ let call_cpdflin cpdflin temp output best_password =
             Sys.command command
         | _ ->
             let command = 
-              "DYLD_FALLBACK_LIBRARY_PATH=" ^ Filename.dirname cpdflin ^ " " ^
-              "LD_LIBRARY_PATH=" ^ Filename.dirname cpdflin ^ " " ^
+              "DYLD_FALLBACK_LIBRARY_PATH=" ^ Filename.quote (Filename.dirname cpdflin) ^ " " ^
+              "LD_LIBRARY_PATH=" ^ Filename.quote (Filename.dirname cpdflin) ^ " " ^
               command
             in
               if !debug then prerr_endline command;
diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 3af6bef..f536c06 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -2346,9 +2346,9 @@ let embed_missing_fonts fi fo =
     exit 2
   end;
     let gscall =
-      args.path_to_ghostscript ^
-      " -dNOPAUSE " ^ (if args.gs_quiet then "-dQUIET" else "") ^ " -sDEVICE=pdfwrite -sOUTPUTFILE=" ^ fo ^
-      " -dBATCH " ^ fi
+      Filename.quote args.path_to_ghostscript ^
+      " -dNOPAUSE " ^ (if args.gs_quiet then "-dQUIET" else "") ^ " -sDEVICE=pdfwrite -sOUTPUTFILE=" ^ Filename.quote fo ^
+      " -dBATCH " ^ Filename.quote fi
     in
       match Sys.command gscall with
       | 0 -> exit 0
@@ -2365,9 +2365,9 @@ let mend_pdf_file_with_ghostscript filename =
   let tmpout = Filename.temp_file "cpdf" ".pdf" in
     tempfiles := tmpout::!tempfiles;
     let gscall =
-      args.path_to_ghostscript ^
-      " -dNOPAUSE " ^ (if args.gs_quiet then "-dQUIET" else "") ^ " -sDEVICE=pdfwrite -sOUTPUTFILE=" ^ tmpout ^
-      " -dBATCH " ^ filename
+      Filename.quote args.path_to_ghostscript ^
+      " -dNOPAUSE " ^ (if args.gs_quiet then "-dQUIET" else "") ^ " -sDEVICE=pdfwrite -sOUTPUTFILE=" ^ Filename.quote tmpout ^
+      " -dBATCH " ^ Filename.quote filename
     in
       match Sys.command gscall with
       | 0 -> Printf.eprintf "Succeeded!\n"; flush stderr; tmpout
@@ -2964,6 +2964,7 @@ let write_image pdf resources name image =
         close_out fh;
       (* If pnmtopng is present, convert the pnm to a PNG. *)
       begin match
+        (* FIXME: Use Filename.quote here *)
         Sys.command ("pnmtopng -gamma 0.45 -quiet " ^ "\"" ^ name ^ ".pnm\"" ^ "> \"" ^ name ^ ".png\" 2>" ^ null_device)
       with
       | 0 -> Sys.remove (name ^ ".pnm")
@@ -3273,6 +3274,7 @@ let startends_of_range x =
 (* Calculating margins *)
 let calculate_margins filename pdf (s, e) =
   (* Call ghostscript *)
+  (* FIXME: Use Filename.quote here *)
   let gscall =
    args.path_to_ghostscript ^
    " -dSAFER -dNOPAUSE -dBATCH -sDEVICE=bbox -r1200"
@@ -4656,9 +4658,9 @@ let gs_malformed_force fi fo =
     exit 2
   end;
     let gscall =
-      args.path_to_ghostscript ^
-      " -dNOPAUSE " ^ (if args.gs_quiet then "-dQUIET" else "") ^ " -sDEVICE=pdfwrite -sOUTPUTFILE=" ^ fo ^
-      " -dBATCH " ^ fi
+      Filename.quote args.path_to_ghostscript ^
+      " -dNOPAUSE " ^ (if args.gs_quiet then "-dQUIET" else "") ^ " -sDEVICE=pdfwrite -sOUTPUTFILE=" ^ Filename.quote fo ^
+      " -dBATCH " ^ Filename.quote fi
     in
       match Sys.command gscall with
       | 0 -> exit 0