void usage(const char *progname)
{
    const char* progname_real; /* contains the real name of the program (without path) */

    progname_real = strchr(progname, '/');
    if (progname_real == NULL) /* no path in progname: use progname */
    {
        progname_real = progname;
    }
    else
    {
        progname_real++;
    }

    fprintf(stderr, "\nusage: %s [ { -g <password length>] | [-p <password> } ] <keyfile>\n\n", progname_real);
}
void usage(const char *progname)
{
    const char* progname_real;  

    progname_real = strchr(progname, '/');
    if (progname_real == NULL)  
    {
        progname_real = progname;
    }
    else
    {
        progname_real++;
    }

    fprintf(stderr, "\nusage: %s [ { -g <password length>] | [-p <password> } ] <keyfile>\n\n", progname_real);
}