simple command line interface (CLI) architecture

When you think about it, what you need is a loop (because you want to do it
over and over), a read, some parsing logic and a something to do. Try that
format...

while (true) {
  printf("Enter cmd>");
  fgets();
  i = parse()    // for example
  switch( i ) {
    case cmd1:
      break;
    case cmd2:
      break;
    default:
      printf("Unknown Command\n");
  }
}

char *cmds[4] {"cmd1", "cmd2", "cmd3", "" };

int parse( char *str_in ) {             // there are many ways to do this -
mostly depending on what format the command is to take.
  char * parsed[20];
  int parse_i = 0;
  char *p;
  int i;

  p = strtok( str_in, " ," ); // parse "cmd1 arg1, arg2"
  do {
    parsed[parse_i++] = p;
    p = strtok( NULL, " ," );
  } while ( !*p);

  for ( i=0; *cmd[i], i++) {
    if ( strcmp ( parsed[0], cmds[i]) == 0)
      return i;
    return -1;
}

When I needed a highly reliable embedded parser, I used flex and bison
to generate it. It is possible to develop a bulletproof parser that
can be easily extended should need arise. The initial learning curve
can be steep, however.