How? copy to dir those .html files in the working directory which are newer or don't exist in the destination directory

Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell.

Bash or Shell is a command line tool that is used in open science to efficiently manipulate files and directories.

The name bash is an acronym of "Bourne-again SHell" which is a pun on Stephen Bourne, author of the Bourne shell. Bash is a superset of the earlier shell, and generally compatible with Bourne shell programs.