Update:
1. Good news. After deleting the Spotlight index and reindexing from scratch, its size has been reduced from 59 GB to 27 GB (32 GB less!!!). Really amazing. It would be great if macOS could warn about it so that the user could manually rebuild it when desired (overnight, etc).
2. On the other hand, searching the Internet I have found that besides the Terminal command above (example below):
sudo du -sh /.Spotlight-V100
that generates
27G /.Spotlight-V100
there is another one which generates more information (example below):
sudo du -hcd 1 /.Spotlight-V100
showing
4.0K /.Spotlight-V100/Store-V1
27G /.Spotlight-V100/Store-V2
27G /.Spotlight-V100
27G total
3. As reported above, the Terminal command
sudo mdutil -E /
triggers the deletion of the Spotlight index and the automatic re-indexing!!! As shown here:
Terminal commands for improving Spotlight
Re-index an entire drive
If you are having problems with your Spotlight index, you might want to start over and re-index your hard drive. In the Terminal, type sudo mdutil -E / and hit return. You may have to enter your password. The existing Spotlight index will be deleted, and Spotlight will start creating a new index in the background.
http://www.macosxtips.co.uk/index_files/terminal-commands-for-improving-spotlight.php
4. Finally, as asked above, which Terminal command should be used to check if the Mac "is, or is not" indexing the Spotlight index in such moment, in case that the GUI progress bar fails to show the expected progress bar when the Mac is actually indexing Spotlight?
Thanks for all!
