Set default applications for document types and URL schemes on macOS.

# To set Safari as the default handler for HTML documents:
duti -s <com.apple.Safari> <public.html> all

# To set VLC as the default viewer for files with .m4v extensions:
duti -s <org.videolan.vlc> <m4v> viewer

# To set Finder as the default handler for the ftp:// URL scheme:
duti -s <com.apple.Finder> <ftp>

# To display information about the default application for a given extension:
duti -x <ext>

# To display the default handler for a given UTI:
duti -d <uti>

# To display all handlers of a given UTI:
duti -l <uti>