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

void cpy(char** d, char** s) {
    int n = strlen(*s);
    (*d) = (char*)malloc(sizeof(char) * n);
    for (int i = 0; i < n; i++) {
        (*d)[i] = (*s)[i];
    }
}

char* get_command(char* commands[], int n) {
    int size = n;
    for (int i = 0; i < n; i++) {
        size += strlen(commands[i]);
    }
    char* result = (char*)malloc(sizeof(char) * size);
    int itr = 0;
    for (int i = 0; i < n; i++) {
        int cur_len = strlen(commands[i]);
        for (int j = 0; j < cur_len; j++) {
            result[itr++] = commands[i][j];
        }
        result[itr++] = ' ';
    }
    result[itr - 1] = '\0';
    return result;
}


FILE* execute(char* commands[], int n, const char* type) {
    FILE* stream = popen(get_command(commands, n), type);
    return stream;
}


int main(int argc, char* argv[]) {
    if (argc < 3) {
        printf("WRONG INPUT\n");
        return 1;
    }

    int size1 = 1;
    char border = 0;
    int size2 = 1;
    for (int i = 2; i < argc; i++) {
        if (argv[i][0] != '-') {
            border = 1;
        } else if (border) {
            size2++;
        } else {
            size1++;
        }
    }

    char* argv1[size1 + 1];
    argv1[size1] = NULL;

    char* argv2[size2 + 1];
    argv2[size2] = NULL;

    for (int i = 0; i < size1; i++) {
        cpy(&argv1[i], &argv[i + 1]);
    }

    for (int i = 0; i < size2; i++) {
        cpy(&argv2[i], &argv[i + 1 + size1]);
    }

    FILE* first_stream = execute(argv1, size1, "r");
    FILE* second_stream = execute(argv2, size2, "w");

    const int BUFFER_SIZE = 1 << 10;
    char BUFFER[BUFFER_SIZE];

    while (fgets(BUFFER, sizeof(BUFFER), first_stream)) {
        fprintf(second_stream, "%s", BUFFER);
    }

    return 0;
}