Jaz Fresh pointed out that if you used "-r [number]" as was wrongly described

Jaz Fresh pointed out that if you used "-r [number]" as was wrongly described
in the man page, curl would send an invalid HTTP Range: header. The correct
way would be to use "-r [number]-" or even "-r -[number]". Starting now,
curl will warn if this is discovered, and automatically append a dash to the
range before passing it to libcurl.