logFD = -1;

        /* Truncate the log to get rid of messages about substitutions
           etc. on the remote system. */
        if (lseek(logFD.get(), SEEK_SET, 0) != 0)
            throw SysError("seeking to the start of log file ‘%s’", result.logFile);
        if (ftruncate(logFD.get(), 0) == -1)
            throw SysError("truncating log file ‘%s’", result.logFile);

        logFD = -1;