root="/xdata/simon/ipwgml/satrain/gmi/"

total=$(find "$root" -type f -name "*.nc" | wc -l | tr -d ' ')
i=0
find "$root" -type f -name "*.nc" -print0 |
	while IFS= read -r -d '' file; do
		i=$((i + 1))
		printf "\r[%d/%d] Updating %s" "$i" "$total" "$file"
		ncatted -h -O \
			-a version,global,o,c,"1.1" \
			-a Conventions,global,d,, \
			-a history,global,d,, \
			"$file"
		done
		printf "\nDone.\n"