void usage(const char *zArgv0){
  fprintf(stderr, 
"Usage: %s ?OPTIONS? TARGET-DB RBU-DB\n"
"\n"
"Where options are:\n"
"\n"
"    -step NSTEP\n"

"    -vacuum\n"

"\n"
"  If the -vacuum switch is not present, argument RBU-DB must be an RBU\n"
"  database containing an update suitable for target database TARGET-DB.\n"
"  Or, if -vacuum is specified, then TARGET-DB is a database to vacuum using\n"
"  RBU, and RBU-DB is used as the state database for the vacuum (refer to\n"
"  API documentation for details).\n"
"\n"
................................................................................
  int i;
  const char *zTarget;            /* Target database to apply RBU to */
  const char *zRbu;               /* Database containing RBU */
  char zBuf[200];                 /* Buffer for printf() */
  char *zErrmsg;                  /* Error message, if any */
  sqlite3rbu *pRbu;               /* RBU handle */
  int nStep = 0;                  /* Maximum number of step() calls */

  int bVacuum = 0;

  int rc;
  sqlite3_int64 nProgress = 0;
  int nArgc = argc-2;

  if( argc<3 ) usage(argv[0]);
  for(i=1; i<nArgc; i++){
    const char *zArg = argv[i];
    int nArg = strlen(zArg);
    if( nArg>1 && nArg<=8 && 0==memcmp(zArg, "-vacuum", nArg) ){
      bVacuum = 1;




    }else if( nArg>1 && nArg<=5 && 0==memcmp(zArg, "-step", nArg) && i<nArg-1 ){
      i++;
      nStep = atoi(argv[i]);





    }else{
      usage(argv[0]);
    }
  }

  zTarget = argv[argc-2];
  zRbu = argv[argc-1];
................................................................................
  ** regular RBU update handle otherwise.  */
  if( bVacuum ){
    pRbu = sqlite3rbu_vacuum(zTarget, zRbu);
  }else{
    pRbu = sqlite3rbu_open(zTarget, zRbu, 0);
  }
  report_rbu_vfs(pRbu);










  /* If nStep is less than or equal to zero, call
  ** sqlite3rbu_step() until either the RBU has been completely applied
  ** or an error occurs. Or, if nStep is greater than zero, call
  ** sqlite3rbu_step() a maximum of nStep times.  */

  for(i=0; (nStep<=0 || i<nStep) && sqlite3rbu_step(pRbu)==SQLITE_OK; i++);
















  nProgress = sqlite3rbu_progress(pRbu);
  rc = sqlite3rbu_close(pRbu, &zErrmsg);


  /* Let the user know what happened. */
  switch( rc ){
    case SQLITE_OK:
      sqlite3_snprintf(sizeof(zBuf), zBuf,
          "SQLITE_OK: rbu update incomplete (%lld operations so far)\n",
          nProgress

void usage(const char *zArgv0){
  fprintf(stderr, 
"Usage: %s ?OPTIONS? TARGET-DB RBU-DB\n"
"\n"
"Where options are:\n"
"\n"
"    -step NSTEP\n"
"    -statstep NSTATSTEP\n"
"    -vacuum\n"
"    -presql SQL\n"
"\n"
"  If the -vacuum switch is not present, argument RBU-DB must be an RBU\n"
"  database containing an update suitable for target database TARGET-DB.\n"
"  Or, if -vacuum is specified, then TARGET-DB is a database to vacuum using\n"
"  RBU, and RBU-DB is used as the state database for the vacuum (refer to\n"
"  API documentation for details).\n"
"\n"
................................................................................
  int i;
  const char *zTarget;            /* Target database to apply RBU to */
  const char *zRbu;               /* Database containing RBU */
  char zBuf[200];                 /* Buffer for printf() */
  char *zErrmsg;                  /* Error message, if any */
  sqlite3rbu *pRbu;               /* RBU handle */
  int nStep = 0;                  /* Maximum number of step() calls */
  int nStatStep = 0;              /* Report stats after this many step calls */
  int bVacuum = 0;
  const char *zPreSql = 0;
  int rc;
  sqlite3_int64 nProgress = 0;
  int nArgc = argc-2;

  if( argc<3 ) usage(argv[0]);
  for(i=1; i<nArgc; i++){
    const char *zArg = argv[i];
    int nArg = strlen(zArg);
    if( nArg>1 && nArg<=8 && 0==memcmp(zArg, "-vacuum", nArg) ){
      bVacuum = 1;
    }else if( nArg>1 && nArg<=7 
           && 0==memcmp(zArg, "-presql", nArg) && i<nArg-1 ){
      i++;
      zPreSql = argv[i];
    }else if( nArg>1 && nArg<=5 && 0==memcmp(zArg, "-step", nArg) && i<nArg-1 ){
      i++;
      nStep = atoi(argv[i]);
    }else if( nArg>1 && nArg<=9 
           && 0==memcmp(zArg, "-statstep", nArg) && i<nArg-1 
    ){
      i++;
      nStatStep = atoi(argv[i]);
    }else{
      usage(argv[0]);
    }
  }

  zTarget = argv[argc-2];
  zRbu = argv[argc-1];
................................................................................
  ** regular RBU update handle otherwise.  */
  if( bVacuum ){
    pRbu = sqlite3rbu_vacuum(zTarget, zRbu);
  }else{
    pRbu = sqlite3rbu_open(zTarget, zRbu, 0);
  }
  report_rbu_vfs(pRbu);

  if( zPreSql && pRbu ){
    sqlite3 *db = sqlite3rbu_db(pRbu, 0);
    rc = sqlite3_exec(db, zPreSql, 0, 0, 0);
    if( rc==SQLITE_OK ){
      sqlite3 *db = sqlite3rbu_db(pRbu, 1);
      rc = sqlite3_exec(db, zPreSql, 0, 0, 0);
    }
  }

  /* If nStep is less than or equal to zero, call
  ** sqlite3rbu_step() until either the RBU has been completely applied
  ** or an error occurs. Or, if nStep is greater than zero, call
  ** sqlite3rbu_step() a maximum of nStep times.  */
  if( rc==SQLITE_OK ){
    for(i=0; (nStep<=0 || i<nStep) && sqlite3rbu_step(pRbu)==SQLITE_OK; i++){
      if( nStatStep>0 && (i % nStatStep)==0 ){
        sqlite3_int64 nUsed;
        sqlite3_int64 nHighwater;
        sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &nUsed, &nHighwater, 0);
        fprintf(stdout, "memory used=%lld highwater=%lld", nUsed, nHighwater);
        if( bVacuum==0 ){
          int one;
          int two;
          sqlite3rbu_bp_progress(pRbu, &one, &two);
          fprintf(stdout, "  progress=%d/%d\n", one, two);
        }else{
          fprintf(stdout, "\n");
        }
        fflush(stdout);
      }
    }
    nProgress = sqlite3rbu_progress(pRbu);
    rc = sqlite3rbu_close(pRbu, &zErrmsg);
  }

  /* Let the user know what happened. */
  switch( rc ){
    case SQLITE_OK:
      sqlite3_snprintf(sizeof(zBuf), zBuf,
          "SQLITE_OK: rbu update incomplete (%lld operations so far)\n",
          nProgress