Wordpress - Link to Download Latest WordPress PLUGIN Version

https://downloads.wordpress.org/plugin/{plugin-name}.latest-stable.zip

The structure should be the same for all WordPress.org plugins and the link you're looking for is:

https://downloads.wordpress.org/plugin/backupwordpress.latest-stable.zip.

You can see an example here on how this might be used.

wp plugin update backupwordpress

Sounds like what you are really after is wp-cli which will let you write shell script that automate such tasks.

Related