tsoding.nobuild/tools/cat.c

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

void cat_file(const char *file_path)
{
    FILE *f = fopen(file_path, "r");
    if (f == NULL) {
        fprintf(stderr, "ERROR: could not open file %s: %s\n",
                file_path, strerror(errno));
        exit(1);
    }

    static char cat_buffer[4098];

    while (!feof(f)) {
        size_t n = fread(cat_buffer,
                         sizeof(cat_buffer[0]),
                         sizeof(cat_buffer) / sizeof(cat_buffer[0]),
                         f);
        fwrite(cat_buffer,
               sizeof(cat_buffer[0]),
               n,
               stdout);
    }

    fclose(f);
}

int main(int argc, char **argv)
{
    if (argc < 2) {
        fprintf(stderr, "USAGE: cat <files...>");
        exit(1);
    }

    for (int i = 1; i < argc; ++i) {
        cat_file(argv[i]);
    }

    return 0;
}