Convert Textile Markup to Markdown¶

pandoc --from textile --to markdown "input.textile" -o "output.md"

Multiple files
To convert a directory full of textile files (including files in nested directories) to markdown, you need to loop over each file and call pandoc each time:

for textile_filename in ./**/*.textile; do
    markdown_filename="${textile_filename%.textile}.md"
    printf "Converting %s to %s\n" $textile_filename $markdown_filename
    pandoc --from textile --to markdown $textile_filename -o $markdown_filename
done

Some issues with the markdown output:
The metadata header (YAML Front Matter) is broken, and requires reformatting to its original. The metadata header between textile and markdown is the same, so it should not have to change.
New lines are added into paragraphs to make them shorter than a certain cahracter length, so you have to remove extra new lines in all your sentences. Instead of one long line of 500 characters (your paragraph), you'll get 8 lines with about 80 characters each.
Feel free to add to this list if you find something annoying, or if you find a way to workaround these. There is much more general information in the Pandoc manual but it doesn't cover conversion in much depth.