I do use:
curl 7.33.0 (x86_64-unknown-linux-gnu) libcurl/7.33.0 OpenSSL/1.0.0 zlib/1.2.3
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtsp smtp smtps telnet tftp
Features: GSS-Negotiate IPv6 Largefile NTLM NTLM_WB SSL libz
Invoking a URL with:
$ curl -i -L -o /dev/null -k --negotiate -u : $URL
works as expected. Negotiate auth is performed. When I transform this to a param file and pass with -K
$ curl -K params.txt
Warning: params.txt:6: warning: '-u' requires parameter
Interestingly, if I set -u foo:bar in the param file, the download works as expected.
The -u in the params file should behave same as in the first example.