mxcl/homebrew — pull request #16516 by sjackman (2012-12-11 16:38:38+00:00)
Title: Use `du -s` rather than `du -d0`

The option `du -s` is equivalent to `du -d0`. The former is a POSIX standard
(IEEE Std 1003.1-2008), whereas the latter is a BSD extension.

From the BSD man page:
`-s Display an entry for each specified file. (Equivalent to -d 0)`

From SUSv4:
`-s Instead of the default output, report only the total sum for each of the specified files.`
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/du.html