SQLite

  "        determines the column names.",
  "     *  If neither --csv or --ascii are used, the input mode is derived",
  "        from the \".mode\" output mode",
  "     *  If FILE begins with \"|\" then it is a command that generates the",
  "        input text.",
#endif
#ifndef SQLITE_OMIT_TEST_CONTROL
  ",imposter INDEX TABLE    Create imposter table TABLE on index INDEX",
#endif
  ".indexes ?TABLE?         Show names of indexes",
  "                           If TABLE is specified, only show indexes for",
  "                           tables matching TABLE using the LIKE operator.",
#ifdef SQLITE_ENABLE_IOTRACE
  ",iotrace FILE            Enable I/O diagnostic logging to FILE",
#endif
  ".limit ?LIMIT? ?VAL?     Display or change the value of an SQLITE_LIMIT",
  ".lint OPTIONS            Report potential schema issues.",
  "     Options:",
  "        fkey-indexes     Find missing foreign key indexes",
#if !defined(SQLITE_OMIT_LOAD_EXTENSION) && !defined(SQLITE_SHELL_FIDDLE)
  ".load FILE ?ENTRY?       Load an extension library",

  ".save ?OPTIONS? FILE     Write database to FILE (an alias for .backup ...)",
#endif
  ".scanstats on|off|est    Turn sqlite3_stmt_scanstatus() metrics on or off",
  ".schema ?PATTERN?        Show the CREATE statements matching PATTERN",
  "   Options:",
  "      --indent             Try to pretty-print the schema",
  "      --nosys              Omit objects whose names start with \"sqlite_\"",
  ",selftest ?OPTIONS?      Run tests defined in the SELFTEST table",
  "    Options:",
  "       --init               Create a new SELFTEST table",
  "       -v                   Verbose output",
  ".separator COL ?ROW?     Change the column and row separators",
#if defined(SQLITE_ENABLE_SESSION)
  ".session ?NAME? CMD ...  Create or control sessions",
  "   Subcommands:",

  "   stmt                     Show statement stats",
  "   vmstep                   Show the virtual machine step count only",
#if !defined(SQLITE_NOHAVE_SYSTEM) && !defined(SQLITE_SHELL_FIDDLE)
  ".system CMD ARGS...      Run CMD ARGS... in a system shell",
#endif
  ".tables ?TABLE?          List names of tables matching LIKE pattern TABLE",
#ifndef SQLITE_SHELL_FIDDLE
  ",testcase NAME           Begin redirecting output to 'testcase-out.txt'",
#endif
  ",testctrl CMD ...        Run various sqlite3_test_control() operations",
  "                           Run \".testctrl\" with no arguments for details",
  ".timeout MS              Try opening locked tables for MS milliseconds",
  ".timer on|off            Turn SQL timer on or off",
#ifndef SQLITE_OMIT_TRACE
  ".trace ?OPTIONS?         Output each SQL statement as it is run",
  "    FILE                    Send output to FILE",
  "    stdout                  Send output to stdout",

  char *zPat;
  if( zPattern==0
   || zPattern[0]=='0'
   || cli_strcmp(zPattern,"-a")==0
   || cli_strcmp(zPattern,"-all")==0
   || cli_strcmp(zPattern,"--all")==0
  ){
    enum HelpWanted { HW_NoCull = 0, HW_SummaryOnly = 1, HW_Undoc = 2 };
    enum HelpHave { HH_Undoc = 2, HH_Summary = 1, HH_More = 0 };
    /* Show all or most commands
    ** *zPattern==0   => summary of documented commands only
    ** *zPattern=='0' => whole help for undocumented commands
    ** Otherwise      => whole help for documented commands
    */
    enum HelpWanted hw = HW_SummaryOnly;
    if( zPattern!=0 ){
      hw = (*zPattern=='0')? HW_NoCull|HW_Undoc : HW_NoCull;
    }
    enum HelpHave hh = HH_More;
    for(i=0; i<ArraySize(azHelp); i++){
      switch( azHelp[i][0] ){
      case ',':
        hh = HH_Summary|HH_Undoc;
        break;
      case '.':
        hh = HH_Summary;
        break;
      default:
        hh &= ~HH_Summary;
        break;
      }
      if( ((hw^hh)&HH_Undoc)==0 ){
        if( (hh&HH_Summary)!=0 ){
          utf8_printf(out, ".%s\n", azHelp[i]+1);
          ++n;
        }else if( (hw&HW_SummaryOnly)==0 ){
          utf8_printf(out, "%s\n", azHelp[i]);

        }
      }
    }
  }else{
    /* Seek documented commands for which zPattern is an exact prefix */
    zPat = sqlite3_mprintf(".%s*", zPattern);
    shell_check_oom(zPat);
    for(i=0; i<ArraySize(azHelp); i++){
      if( sqlite3_strglob(zPat, azHelp[i])==0 ){
        utf8_printf(out, "%s\n", azHelp[i]);
        j = i+1;
        n++;
      }
    }
    sqlite3_free(zPat);
    if( n ){
      if( n==1 ){
        /* when zPattern is a prefix of exactly one command, then include
        ** the details of that command, which should begin at offset j */
        while( j<ArraySize(azHelp)-1 && azHelp[j][0]==' ' ){
          utf8_printf(out, "%s\n", azHelp[j]);
          j++;
        }
      }
      return n;
    }
    /* Look for documented commands that contain zPattern anywhere.
    ** Show complete text of all documented commands that match. */
    zPat = sqlite3_mprintf("%%%s%%", zPattern);
    shell_check_oom(zPat);
    for(i=0; i<ArraySize(azHelp); i++){
      if( azHelp[i][0]==',' ){
        while( i<ArraySize(azHelp)-1 && azHelp[i+1][0]==' ' ) ++i;
        continue;
      }
      if( azHelp[i][0]=='.' ) j = i;
      if( sqlite3_strlike(zPat, azHelp[i], 0)==0 ){
        utf8_printf(out, "%s\n", azHelp[j]);
        while( j<ArraySize(azHelp)-1 && azHelp[j+1][0]==' ' ){
          j++;
          utf8_printf(out, "%s\n", azHelp[j]);
        }
        i = j;
        n++;
      }
    }