problem parsing a file and then executing 2 commands in pipe - c

Question

I am making a program in which I need to read from a file and execute the command in pipe. The command could be something like "ps -lu user | sort", and I should execute the first command and then the second, in different processes (using fork and exec). The problem comes when I do the exec and it doesn't work correctly.
What I have so far is the following:
`int main(int argc, char* argv[]){
int file = open(argv[1], O_RDONLY);
int fd[2]; int pid;
char s[8192];
int nBytes = read(file, &s, 8192);
char* s2 =malloc(8192); char* s3 = malloc(8192);
char* comando1[8192]; char* comando2[8192];
s2 = strtok(s, "|");
s3 = strtok(NULL, "\n");
comando1[0] = strtok(s2, " ");
int i;
if(s2 != NULL)
for(i = 1; comando1[i] = strtok(NULL, " \t"); i++);
comando2[0] = strtok(s3, " ");
if(s3 != NULL)
for(i = 1; comando2[i] = strtok(NULL, " \t"); i++);
pid = fork();
if(pid == 0){//
pipe(fd);
int pid2 = fork();
if (pid2 > 0){
printf("%s\n", comando1[0]);
close(1);
close(fd[0]); //cerramos stdout y extremo de lectura
dup(fd[1]); close(fd[1]); //redireccionamos salida estándar a la pipe
execvp(comando1[0], &comando1[0]); //ejecutamos el comando 1 con salida pipe
perror("Error");
write(2, "Error en el exec1", 17);
}
else if(pid == 0){
close(fd[1]); close(0); //cerramos extremo de escritura y stdin
dup(fd[0]); close(fd[0]); //redirección entrada estándar a la pipe
printf("%s\n", comando2[0]);
execvp(comando2[0], &comando2[0]); //ejecutamos el comando 1 con salida pipe
perror("Error");
write(2, "Error en el exec2", 17);
}
}
}
`
Which does not work as expected. For a file "file.txt" with the following command: "ps -lu user | sort -n -r", it says:
sort:
illegal option --
usage: sort [-cmu] [-o output] [-T directory] [-S mem] [-z recsz] [-dfiMnr] [-ddfiMnr] [-sdmem] [-sdm] [-z recsz
[-dfiMnr] [-b] [-t char] [-k keydef] [+pos1 [-pos2]] files....
However, if I manually add the parameters keeping everything the same (change execlp to execvp and pass (execlp("ps", "ps", "-lu", "user", 0) and execlp("sort", "sort", 0); the result is as expected (but it is not correct since I am not reading from the file). what could it be due to?