TextBundle Packagizer -- This is a script that helps to create bundled folders of Markdown files. It downloads online-linked images to an assets directory, as well as copies local files to it. It's not finished yet.

packagizer.sh

#!/bin/sh

function usage {
	echo "This script creates a folder containing all linked ![images]()"
	echo "of a Markdown file -- even linked ones from the Internet."
	echo ""
	echo "It takes one argument: the file it should process."
	echo
	echo "When a file argument is present, it creates a new folder for:"
	echo "a) the Markdown file"
	echo "b) and an \"assets\" folder for images"
	echo
	echo "Everything referenced is packaged into one folder."
	return
}

function localize() {
	if [[ $i == *"http"* ]]; then
		echo "Downloading: $fileurl"

		# download file into assets with original name
		cd "$packageName/assets"
		curl -OJ --silent $fileurl
		cd - &>/dev/null

		newname=$(curl --write-out %{filename_effective} --silent --remote-name $fileurl)
	else [[ -e $i ]]
		echo "Copying: $fileurl"

		# copy file into assets
		cd "$packageName/assets"
		cp $fileurl .
		cd - &>/dev/null

		newname=$(basename $fileurl)
	fi
	# replace old with new location
	sed -i "" "s~$fileurl~assets/$newname~" "$packageName/$inFile"
}

### Setup
if [[ -e "$1" ]]; then
	#packageName=$(basename $1)
	packageName="${1%%.*}"

	#Use this to make text bundles:
	#packageName="${1%%.*}.textbundle"

	inFile=$1
elif [[ "$1" == "--help" || "$1" == "-h" ]]; then
	usage
	exit
else
	usage
	echo
	echo "Error: No file input present."
	exit 1
fi

### Create Package Dir
echo "packageName: $packageName"
echo "inFile: $1"

mkdir "$packageName"
mkdir "$packageName/assets"
cp "$inFile" "$packageName"

### Localize files
# catch inline links
targets=($(grep "!\[\](" $inFile))
echo
echo "Processing inline links: ${targets[@]}"

for i in "${targets[@]}"; do
	fileurl=$(echo $i | sed -e "s~\!\[\](\(.*\))~\1~")
	#echo $i
	#echo "fileurl: $fileurl"
	localize $i
done

# catch reference links
targets=($(grep "!\[\]\[" $inFile))
echo
echo "Processing reference links: ${targets[@]}"

#search for reference tags and replace them
for i in "${targets[@]}"; do
	filetag=$(echo $i | sed -e "s~\!\[\]\[\(.*\)\]~\1~")
	fileurl=$(grep "\[$filetag\]:" $inFile | sed -e "s~\[$filetag\]:.\(.*\)~\1~")
	#echo $i
	#echo "fileurl: $fileurl"
	localize $i
done

If this can be finalised and useable on multiple platforms, it could become a lifesaver for folks like me who needs to convert .md files to .textbundle. In my particular case, I can only export entries in Apple Notes in the .md format, and to retain images or documents, I need to convert these to .textbundle files for importing correctly into Craft. Long story short: I cannot find other people making a similar thing on the web, so thumbs up from me regarding this!

+1