use imageMagick and gsed to save count,hex of colors in an image

get-colors.sh

#!/bin/bash
# Return the histogram

fileToWrite="./colors.csv"
filename=""
regex='(\d+): '

if [ "$1" != "" ]; then # Test for positional argument
    if [ -f "$1" ]; then # Test if regular file, not directory
    	filename="$1"

        # Test if a valid file type
    	if [[ $filename == *.png ]] || [[ $filename == *.jpg ]]; then 

            # erase the file
            > $fileToWrite

            # create histogram
            colors=$(convert  "$filename"  -define histogram:unique-colors=true -format %c histogram:info:-)

            # parse histogram
            gsed -rn 's/[ ]+([[:digit:]]+): \([ 0-9]{3},[ 0-9]{3},[ 0-9]{3},[ 0-9]{3}\) (#[A-F0-9]{8}) [A-Za-z0-9\(\),]+$/\1,\2/p' <<< "$colors" > $fileToWrite


    	else
    		echo "Error! Not a valid file type" 1>&2
    		exit 64;
    	fi
    else
    	echo "Error! Not a valid file." 1>&2
    	exit 64;
    fi
else
    echo "Error! No file passed in." 1>&2
    exit 64;
fi