Make Grayscale pdf

makegrayscale.sh

#!/bin/bash

# Uses ghostscript to make a pdf grayscale.
# Helps to see if graphs make sense in grayscale.

COMMAND=gs
COMMAND_OPTS="-sDEVICE=pdfwrite -sColorConversionStrategy=Gray -dProcessColorModel=/DeviceGray -dCompatibilityLevel=1.4 -dAutoRotatePages=/None -dNOPAUSE -dBATCH"
OUTFILE=grayscale.pdf
COMPRESS=0

usage() { echo -e "Usage:\n\t$0 [-o OUTPUT] [-c LEVEL] INPUT_FILE\n\n\
Options:\n\
\t-o OUTPUT: Grayscale pdf is saved to OUTPUT (Default: grayscale.pdf)\n\
\t-c LEVEL: Enables compression. LEVEL is either '0', '1' or '2' (Default: 0)\n" 1>&2; exit 1;}

if ! command -v $COMMAND &> /dev/null
then
    echo "ERROR: \"$COMMAND\" could not be found"
    echo "Make sure that GhostScript is installed"
    exit
fi

while getopts "o:c:" opt; do
	case $opt in
	o)
		OUTFILE=$OPTARG
	;;
	c)
		COMPRESS=$OPTARG
		((COMPRESS == 1 || COMPRESS == 2 || COMPRESS == 0)) || usage
	;;
	\?)
		usage
	;;
	esac
done
shift $((OPTIND-1))

if [ $# -lt 1 ]; 
    then echo "No input file specified"; exit 1;
fi

COMMAND_OPTS="-sOutputFile=$OUTFILE $COMMAND_OPTS"
if [ $COMPRESS -eq "1" ]
then
	COMMAND_OPTS="$COMMAND_OPTS -dPDFSETTINGS=/ebook"
elif [ "$COMPRESS" -eq "2" ]
then
	COMMAND_OPTS="$COMMAND_OPTS -dPDFSETTINGS=/screen"
fi

$COMMAND $COMMAND_OPTS $@