Add this to your Rakefile :
task :np do
note_name =ENV['note'] || 'misc'
note_file = "_posts/#{Time.now.to_i}-#{note_name}.md"
`touch #{note_file}`
end
Create a new post like so:
env note="Jekyll new post rake task" rake np
Now you can edit your post at : _posts/2018-12-24-jekyll-new-post-rake.md