This seems like a bit of a scam:
On your external drives you can prevent the creation of .DS_Store
defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true
defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true
If you really want to continuously delete DS_Store
from both your internal and external hard drives you can set up a cronjob:
15 1 * * * root find / -name '.DS_Store' -type f -delete
Don’t forget:
defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true