#include <stdio.h>
#include <string.h>

int main()
{
  char * word, * unused;
  char * cmd = "ls -la &";

  char temp[1024];
  strcpy( temp, cmd );  /* copy cmd to temp, because strtok() changes input */

  word = strtok_r( temp, " \t", &unused );

  while ( word != NULL )    /** temp: "ls\0-la\0&" **/
  {                         /**                 ^  **/

    printf( "[%s] %s\n", cmd, word );
    /* strcpy() here or save each of the returned pointers */
    word = strtok_r( NULL, " \t", &unused );  /* re-entrant */
  }

  printf( "[%s]\n", cmd );
  printf( "[%s]\n", temp );

  return 0;
}