typical https://gist.github.com/costa/b9570f214c7b7cfdf7d09069f16d7ca8 output on MacOS

gistfile1.txt

$ DU_IGNORES=Volumes ~/local/script/du_sum.rb 
du -I 'Volumes' /
Password:
1550280 du
.20T  /Users
...
| 25.G  /Users/Shared
| | | 24.G  /Users/Shared/iTunes/Music
...
38.G  /Applications
| | 9.1G  /Applications/Xcode.app/Contents
| | | 7.6G  /Applications/Xcode.app/Contents/Developer
| | | | 6.9G  /Applications/Xcode.app/Contents/Developer/Platforms
| | | | | 3.0G  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform
| | | 3.9G  /Applications/Adobe Lightroom Classic/Adobe Lightroom Classic.app/Contents
| | | 3.5G  /Applications/Adobe Photoshop 2021/Adobe Photoshop 2021.app/Contents
16.G  /System
| 14.G  /System/Library
11.G  /usr
| 11.G  /usr/local
| | 7.8G  /usr/local/Cellar
8.2G  /Library
| 5.2G  /Library/Application Support
| | 3.5G  /Library/Application Support/Adobe
| 5.5G  /private/var
| | 3.7G  /private/var/db