diff --git a/home/local/bin/merge-pdf b/home/local/bin/merge-pdf
index c5b4e62..a2d0de5 100755
--- a/home/local/bin/merge-pdf
+++ b/home/local/bin/merge-pdf
@@ -1,8 +1,74 @@
 #! /usr/bin/env nix-shell
-#! nix-shell -i bash -p ghostscript
+#! nix-shell -i bash -p ghostscript -p coreutils
 #
 # Local Variables:
 # mode: sh
 # End:
+#
 
-gs -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=- -dBATCH "$@"
+workdir=
+keep_workdir=false
+output=-
+
+function usage {
+    cat <<EOF
+usage: merge-pdf [options] files...
+
+options:
+  -o FILE    write result to FILE (default: -)
+EOF
+}
+
+function cleanup {
+    if [ x"${keep_workdir}" != x"true" ]; then
+        if [ -d "${workdir}" ]; then
+            rm -rf "${workdir}"
+        fi
+    fi
+}
+
+trap "cleanup" EXIT
+
+while getopts ":ho:k" o; do
+   case "$o" in
+       h)
+           usage
+           exit 0
+           ;;
+       o)
+           output="$OPTARG"
+           ;;
+       k)
+           keep_workdir=true
+           ;;
+       *)
+           usage
+           exit 1
+           ;;
+   esac
+done
+
+shift $((OPTIND - 1))
+
+workdir=$(mktemp -d)
+
+echo >&2 "[INFO] Putting temporary files into ${workdir}"
+
+files=()
+for f; do
+    fname=$(basename "$f" .pdf)
+    of="${workdir}/${fname}.ps"
+    echo >&2 "[PS  ] \"${f}\" -> \"${of}\""
+    pdf2ps "$f" "${of}" >&/dev/null
+    files+=("$of")
+done
+
+echo >&2 "[PDF ] combining ${#files[@]} file(s) into ${output}"
+
+gs -dNOPAUSE -sDEVICE=pdfwrite \
+    -dPDFSETTINGS=/prepress \
+    -sPAPERSIZE=a4 \
+    -sFIXEDMEDIA \
+    -sOUTPUTFILE="${output}" \
+    -dBATCH \
+    "${files[@]}" >&/dev/null