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

int main(int argc, char** argv)
{
    FILE* f;

    if (argc < 2)
    {
        fprintf(stderr, "usage: %s [file]", argv[0]);
        return 1;
    }

    f = fopen(argv[1], "w");
    if (!f)
    {
        perror(argv[1]);
        return 1;
    }

    char buffer[4096];

    while (1)
    {
        char* rc = fgets(buffer, sizeof(buffer), stdin);
        if (rc == 0) break;
        fputs(buffer, f);
    }

    fclose(f);

    return 0;
}