Use vim to convert a file of markdown headings to org heading.
For example, change this:
# heading one
body
##heading two
### heading three
body
to this:
* heading one
body
**heading two
****** heading six
Only a continues sequence of '#' starting at column 0 should be substituted with an equal number of '*'.
This substitutes only the first '#' with '*':
%s/^[#]/*/c
But there can be up to six '#' to substitute.