Node.js

Create a Hard Link on an SFTP Server

Demonstrates the Chilkat SFtp.HardLink method, which creates a hard link to an existing remote file. The first argument is the existing file and the second is the new link path. It uses the OpenSSH hardlink@openssh.com extension and succeeds only when the server supports it.

Background: A hard link is a second name for the same file data, not a pointer to a path: both names are equal, the data persists until the last name is removed, and there is no "original" to break. Unlike a symbolic link it cannot span filesystems and cannot target a directory. Because it depends on a non-standard OpenSSH extension, expect it to fail against servers that do not implement it.

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function chilkatExample() {

    var success = false;

    //  Demonstrates the SFtp.HardLink method, which creates a hard link to an existing remote file.
    //  The 1st argument is the existing file and the 2nd is the new link path.

    var sftp = new chilkat.SFtp();

    //  Connect, authenticate, and initialize the SFTP subsystem.
    var port = 22;
    success = sftp.Connect("sftp.example.com",port);
    if (success == false) {
        console.log(sftp.LastErrorText);
        return;
    }

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    var password = "mySshPassword";

    success = sftp.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        console.log(sftp.LastErrorText);
        return;
    }

    success = sftp.InitializeSftp();
    if (success == false) {
        console.log(sftp.LastErrorText);
        return;
    }

    //  Create a hard link.  This uses the OpenSSH hardlink@openssh.com extension and succeeds only
    //  when the server supports it.
    success = sftp.HardLink("subdir/data.bin","subdir/data_backup.bin");
    if (success == false) {
        console.log(sftp.LastErrorText);
        return;
    }

    console.log("Hard link created.");

    sftp.Disconnect();

}

chilkatExample();