My small but smart script for batch converting (and other manipulation) images to cmyk colorspace.

Convert2cmyk.sh

#!/bin/bash
# What do: Converting, manipulating etc. jpegs to CMYK colorspace
# Script is absolutly free/libre, but no guarantee.
# Author: Ondřej Profant

function 2cmyk {
 echo -e "[info]\tThis operation needs a lot of CPU resources. Probably will take a long time."
 for i in *.jpg ; do
	mv $i ${i%.jpg}rgb.jpg
	convert -depth 8 -colorspace cmyk -alpha Off ${i%.jpg}rgb.jpg ${i%.jpg}cmyk.jpg 
 done;
}

function fin {
 case $1 in
  rgb)
	for i in *rgb.jpg; do
		mv $i ${i%rgb.jpg}.jpg
	done;
  ;;
 cmyk)
	for i in *cmyk.jpg; do
		mv $i ${i%cmyk.jpg}.jpg
	done;
  ;;
 *)
	usage
	exit;
  ;;
 esac;
}

function del {
 echo "Are you sure you want to delete all $1 files? (y/n)";
 read x ;
 if [ $x = "y" ] ; then :
	case $1 in
	rgb)  rm *rgb.jpg ;;
	cmyk) rm *cmyk.jpg ;;
	*) usage;;
	esac;
 else 
	exit; 
 fi;
}

function checkPDF {
 identify -verbose ${1}  | grep Colorspace
}

function usage {
	echo "USAGE:"
	echo -e "\t$0 convert\t\tconvert all *jpg in folder"
	echo -e "\t$0 check [file]\tcheck pdf colorspace (file can be pdf)"
	echo -e "\t$0 replace\t\treplace rgp-*.jpg by cmyk-*.jpg"
	echo -e "\t$0 fin [rgb/cmyk]\tdelete colorspace sufix"
	echo -e "\t$0 del [rgb/cmyk]\tdelete files with sufix"
}

# == MAIN ==
if convert -version > /dev/null ; then :
else 
	echo "ImageMagick mising";
	exit;
fi;


case $1 in 
con*)
	2cmyk
	echo -e "[info]\t Your old pics be renamed, new cmyk was created. For finish use:"
	echo -e "\t$0 fin [cmyk/rgb]"
;;
check)  checkPDF $2	;;
info)	checkPDF $2	;;
fin*)	fin $2		;;
del)	del $2		;;
*)	usage		;;
esac;