Convert png to eps . Requirements convert Unix command

convpng2eps.sh

#!/bin/bash
 
# dependencies
# + convert

SCRIPT_DIR=`dirname $0`
 
# If ./eps directory doesn't exist, make directory .
if [ ! -d ${SCRIPT_DIR}/eps ]
then
    mkdir ${SCRIPT_DIR}/eps
fi
 
PNG_FILES=`ls | grep .png`
for PNG_FILE in ${PNG_FILES[@]}
do
    LEN=${#PNG_FILE}
    END=`expr ${LEN} - 4`
    FILE_NAME=`echo ${PNG_FILE} | cut -c 7-${END}`
    convert ${PNG_FILE} ${SCRIPT_DIR}/eps/${FILE_NAME}.eps
done