toc2md 0.9.5
Insert or update nested chapter numbering and linked Table Of Contents into a MarkDown file
Requires Python: >=3.7

```
INSTALLATION

    $ pip3 install toc2md

HELP

    $ toc2md -h

USAGE

    $ toc2md [-h] [-H] [-V] [-v] [file]


Insert or update nested chapter numbering and linked Table Of Contents into a MarkDown file

If we type at terminal:

    $ toc2md -v example.md

toc2md program:

    - copies `example.md` into a timestamped backup file `example-YYYY.mm.dd-HH:MM:SS.md`
    - writes (only if '-v' is present) on standard output something like:

        file '/home/xxxx/example.md' has been backed up...
        ...into '/home/xxxx/example-2020.06.05-18.19.07.md'

    - reads example.md
    - checks correct heading sequence (see below)
    - deletes old chapter numbering (if any) and old TOC (if any)
    - inserts new nested chapter numbering and new linked TOC
    - rewrites the updated version into example.md
    - writes (only if '-v' is present) on standard output something like:

        file '/home/xxxx/example.md' has been updated

There is neither configuration file nor options. Logic has been kept as simple
as possible, but the file to be processed must obey some rule, as follows.

toc2md processing is driven by headings in input file. A heading for us is a line
which starts with a '#' character. The heading level is the number of leading '#'
characters, between 1 and 6. So a heading is made by:

    - a string of 1 to 6 '#' characters
    - a blank
    - a title

Title must start with an alphabetic character.

'#' characters after the sixth are silently discarded.

The blank after '#' characters if not present is silently inserted.

Any line not starting with '#' is processed as normal text, including MD headings as:

    Something
    ===

or HTML headings like:

    <h3>Something Else</h3>

which are anyway deprecated and must be avoided.

Titles in headings are:

    - level 1 heading: title of the whole document
    - first level 2 heading: title of the TOC
    - following level 2 headings: titles of level 1 chapters (as 1. 2. ...)
    - level 3 headings: titles of level 2 chapters (as 1.1. 1.2. ...)
    - level 4 headings: titles of level 3 chapters (as 1.1.1. 1.1.2. ...)
    - level 5 headings: titles of level 4 chapters (as 1.1.1.1. 1.1.1.2. ...)
    - level 6 headings: titles of level 5 chapters (as 1.1.1.1.1. 1.1.1.1.2. ...)

So the input file must contain the following headings, freely intermixed with
normal text, but in this order:

    - one level 1 heading with title of the whole document
    - one level 2 heading with title of the TOC
    - one level 2 heading with title of the first level 1 chapter (1.)
    - zero or more level 2..6 headings with titles of level 1..5 chapters

Beware: no heading can ever have a level higher than that of the previous
heading plus one.

Each non-heading line in input is transcribed as it is into output, except for
those between the first and second level 2 headings. These lines are supposed to
be the old TOC and hence are deleted and replaced in output by the new TOC.

Chapter numbering in input headings is deleted and replaced in output by the new
chapter numbering.

For further details type at terminal:

    $ toc2md -H

POSITIONAL ARGUMENTS

  file              markdown file to be backed up, read, processed and
                    rewritten

OPTIONAL ARGUMENTS

  -h, --help        show this help message and exit
  -H, --user-guide  open User Guide in PDF format and exit
  -V, --version     show program's version number and exit
  -v, --verbose     show what happens
```