$ curl -I https://auth.example.com --cookie-jar ./cookie.txt --basic --user somedude
200 OK
[...]
Set-Cookie: session=mdkfUHAUnjdfj[...] path=/; expires=Sat, 15 Apr 2017 04:08:35 -0000; secure; HttpOnly
[...]

$ cat ./cookie.txt
# Netscape HTTP Cookie File
# https://curl.haxx.se/docs/http-cookies.html
# This file was generated by libcurl! Edit at your own risk.

#HttpOnly_auth.example.com	FALSE	/	TRUE	1492227302	session	mdkfUHAUnjdfj[...]