curl_easy_setopt.3: clarify the SSH KEYFILE options usage

option is only for SCP and SFTP transfers. (Added in 7.17.1)

.IP CURLOPT_SSH_PUBLIC_KEYFILE

Pass a char * pointing to a file name for your public key. If not used,

libcurl defaults to using \fB~/.ssh/id_dsa.pub\fP.

(Added in 7.16.1)

libcurl defaults to \fB$HOME/.ssh/id_dsa.pub\fP if the HOME environment

variable is set, and just "id_dsa.pub" in the current directory if HOME is not

set.  (Added in 7.16.1)

.IP CURLOPT_SSH_PRIVATE_KEYFILE

Pass a char * pointing to a file name for your private key. If not used,

libcurl defaults to using \fB~/.ssh/id_dsa\fP.  If the file is

password-protected, set the password with \fICURLOPT_KEYPASSWD\fP. (Added in

7.16.1)

libcurl defaults to \fB$HOME/.ssh/id_dsa\fP if the HOME environment variable

is set, and just "id_dsa" in the current directory if HOME is not set.  If the

file is password-protected, set the password with

\fICURLOPT_KEYPASSWD\fP. (Added in 7.16.1)

.IP CURLOPT_SSH_KNOWNHOSTS

Pass a pointer to a zero terminated string holding the file name of the

known_host file to use.  The known_hosts file should use the OpenSSH file