CURLOPT_SSH_PRIVATE_KEYFILE(3)

💖 CURLOPT_SSH_PRIVATE_KEYFILE 💖

okay so bestie, this is a libcurl page from the Library Functions Manual, and it's about telling curl where your SSH private key lives. literally the whole vibe. ✨

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🌸 NAME 🌸

CURLOPT_SSH_PRIVATE_KEYFILE — the private key file you use for SSH auth, no cap 🗝️

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🎀 SYNOPSIS 🎀

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_PRIVATE_KEYFILE,
                          char *filename);

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🦋 DESCRIPTION 🦋

So you pass a char pointer that points to a filename — that's your private key, bestie. 🔑

If you don't use this option, libcurl goes ahead and defaults to $HOME/.ssh/id_rsa or $HOME/.ssh/id_dsa if the HOME environment variable is set, and it looks in the current directory if HOME is not set. the way it just picks for you 💅

If the file is password-protected, set that password with CURLOPT_KEYPASSWD(3). don't leave her hanging. 🫶

The SSH library derives the public key from this private key when it can. But listen — if the SSH library cannot derive the public key from the private one and no public one is provided with CURLOPT_SSH_PUBLIC_KEYFILE(3), the transfer fails. like, dead. 💀 so give her what she needs.

Good news though: the application does not have to keep the string around after setting this option. set it and forget it, icon behavior ⭐

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🧚 DEFAULT 🧚

As explained above ✨ (aka the $HOME/.ssh/id_rsa / $HOME/.ssh/id_dsa / current-directory situation)

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🌈 PROTOCOLS 🌈

This functionality affects scp and sftp 🚀

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💜 EXAMPLE 💜

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/file");
    curl_easy_setopt(curl, CURLOPT_SSH_PRIVATE_KEYFILE,
                     "/home/clarkkent/.ssh/id_rsa");
    curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "password");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

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⭐ AVAILABILITY ⭐

Added in curl 7.16.1 👑

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🔥 RETURN VALUE 🔥

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK 😌, non-zero means an error occurred 😭 — see libcurl-errors(3) for the full tea.

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🍓 SEE ALSO 🍓

• CURLOPT_SSH_AUTH_TYPES(3)
• CURLOPT_SSH_PUBLIC_KEYFILE(3)

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okay that's the whole page, bestie, you ate 💅✨ this was libcurl, dated 2026-10-12, and the page is CURLOPT_SSH_PRIVATE_KEYFILE(3) — mwah, go forth and SSH 🦋💖