BASH script to copy only used images

copy-used-images.sh

#!/bin/bash
# This script copies all images, needed by SOURCE_XML, to OUTPUT_PREFIX.  
# Copyright © reflexing@reflexing.ru, MIT License
# Used in makefile this way: $(TOOLS_DIR)/copy-used-images.sh $(SOURCE) $(SOURCE)/$(PROJECT_NAME).xml $(realpath $(TOOLS_DIR)) $(OUTPUT_PREFIX) $(CALLOUTS_DIR) $(ADMON_DIR) $(NAVIG_DIR) $(CALLOUT_EXT) $(ADMON_EXT)

# Assign vars from arguments. Magic.
declare -i i=1
for varname in SOURCE SOURCE_XML TOOLS_DIR OUTPUT_PREFIX CALLOUTS_DIR ADMON_DIR NAVIG_DIR CALLOUT_EXT ADMON_EXT; do
  eval $varname=${!i}
  let i++
done

declare -r noise="\/ > \/ > Object is a number : " # noise to cut from xmllint's output

# Proper determine used images
files=$(echo -e 'setrootns\ncat //@fileref' | xmllint --xinclude --shell $SOURCE_XML \
            | sed -n 's/.*fileref="\([^"]*\)".*/\1/p' | sort | uniq)

mkdir --parents $OUTPUT_PREFIX/images

if [[ -n $files ]]; then
	pushd . && cd $SOURCE && cp --parents --update $files ../$OUTPUT_PREFIX
	popd
fi

# Determining quantity of <calloutlist>s proper way
declare -i num_calloutlists=$(echo -e 'setrootns\nxpath count(//defaultns:calloutlist)' \
                    | xmllint --xinclude --shell $SOURCE_XML \
                    | sed -e "s/$noise//g" \
                    | cut -f9- -d " ")

if [[ $num_calloutlists -gt 0 ]]; then
	# Getting maximum quantity of <callout>s in each <calloutlist>
	declare -i max_callouts=0
	for i in $(eval echo {1..$num_calloutlists}); do
	    declare -i num_callouts=$(echo -e "setrootns\nxpath count((//defaultns:calloutlist)[$i]/defaultns:callout)" \
	                    | xmllint --xinclude --shell $SOURCE_XML \
	                    | sed -e "s/$noise//g" \
	                    | cut -f9- -d " ")
	    if [[ $num_callouts -gt $max_callouts ]]; then
	      max_callouts=$num_callouts
	    fi
	done
	
	if [[ $max_callouts -gt 0 ]]; then	# copy only if there are callouts
		mkdir --parents $OUTPUT_PREFIX/$CALLOUTS_DIR
		eval cp --update $TOOLS_DIR/$CALLOUTS_DIR/{1..$max_callouts}.$CALLOUT_EXT \
			$OUTPUT_PREFIX/$CALLOUTS_DIR
	fi
fi

# Checking if there are particular admonition and copying it
declare -i is_admon=0
for admon in important tip note warning caution; do
    declare -i num_admon=$(echo -e "setrootns\nxpath count(//defaultns:$admon)" \
                    | xmllint --xinclude --shell $SOURCE_XML \
                    | sed -e "s/$noise//g" \
                    | cut -f9- -d " ")
    if [[ $num_admon -gt 0 ]]; then
    	if (( ! is_admon )); then
			is_admon=1
			mkdir --parents $OUTPUT_PREFIX/$ADMON_DIR
		fi

    	cp --update $TOOLS_DIR/$ADMON_DIR/$admon.$ADMON_EXT $OUTPUT_PREFIX/$ADMON_DIR
    fi
done