knazarov.com/bin/mdpage.sh

#!/usr/bin/env bash

set -e

render() {
    NOTITLE="$1"
    LASTLINE=""
    TITLE=""

    while read -r line ; do
        if [[ "$line" =~ ^Subject:\ .*$ ]]; then
            TITLE="${line#* }"
        fi
        if [[ "$line" =~ ^X-Date:\ .*$ ]]; then
            DATE="${line#* }"
        fi
        if [[ ! "$line" =~ ^[^\ ]*:\ .*$ ]]; then
            LASTLINE="$line"
            break
        fi
    done

    {
        [ "$NOTITLE" == "0" ] && echo "# $TITLE";
        echo "$LASTLINE";
        cat
    } | awk -f ./bin/markdown.awk | ./bin/page.sh "$TITLE" "$DATE"

}

NOTITLE=0

if [ "$1" == "--notitle" ]; then
    NOTITLE=1
fi

if [ -t 0 ]; then
    echo "Missing Markdown body"
    exit 1
fi

render "$NOTITLE"