#!/bin/sh

if [ $# -lt 1 ] || [ $# -gt 2 ] || [ "$1" = "-h" ]; then
    cat <<EOF
Usage: ${0##*/} PDFFILE [DESTFILE]

WARNING: use this function with caution.  It may drastically improve compression
of some PDF files, but in some case, the output filesize will be greater! You
should not use it over PDF files embedding pictures as well.
EOF
     exit
fi

if [ ! -f "$1" ]; then
    echo "$1 is not a valid PDF file!"
fi
INPUTFILE="$1"

if [ -z "$2" ]; then
    gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile="${INPUTFILE%%.*}-COMPRESSED.pdf" "${INPUTFILE}"
    rm -rf "${INPUTFILE}"
    mv "${INPUTFILE%%.*}-COMPRESSED.pdf" "${INPUTFILE}"
else
    OUTPUTFILE="$2"
    gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile="${OUTPUTFILE}" "${INPUTFILE}"
fi