mdAddAnchors

#!/bin/bash

# This script will read a markdown file from stdin and will add an html
# anchor tag to each header it sees, and send the result back to stdout.

IFS=''
while read -r line ; do
    if echo "$line" | grep "^[[:space:]]*#\+[[:space:]]\+[^#]\+$" > /dev/null 2>&1 ; then
        # get everything before the heading text
        lead=$(echo "${line}" | sed "s/\([[:space:]]*##*[[:space:]]\+\).*/\1/")
        # get the heading text
        rest=$(echo "${line}" | sed "s/\([[:space:]]*##*[[:space:]]\+\)\(.*\)/\2/")
        # convert the heading into a markdown anchor
        # - remove trailing spaces
        # - convert upper to lower case
        # - remove all punct
        # - convert all spaces to -'s
        ref=$(echo -n "${rest}" | \
                sed "s/[[:space:]]*$//g" | \
                tr "[:upper:]" "[:lower:]" | \
                sed "s/[[:punct:]]*//g" | \
                tr "[:space:]" "-")
        # now add the anchor to the line and print it
        echo "${lead} <a id='${ref}'></a> ${rest}"
    else
        # not a header so just print it
        echo "${line}"
    fi
done