cat.c

   1 /*
   2     Copyright © 2013 Alastair Stuart
   3
   4     This program is open source software: you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation, either version 3 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12     GNU General Public License for more details.
  13 */
  14
  15 #include <stdio.h>
  16 #include <string.h>
  17 #include <errno.h>
  18
  19 #define VERSION "0.01"
  20
  21 void usage(char* program)
  22 {
  23     printf("Usage: %s [options] [file ...]\n", program);
  24     printf("Concatenates file(s) and/or standard input to standard output.\n"
  25            "\n"
  26            "    --help     Print this message.\n"
  27            "    --version  Show version info.\n");
  28 }
  29
  30 int main(int argc, char* argv[])
  31 {
  32     // read from stdin if run with no args
  33     if (argc == 1) {
  34         int c = fgetc(stdin);
  35         while (c != EOF)
  36         {
  37             printf("%c", c);
  38             c = fgetc(stdin);
  39         }
  40
  41         return 0;
  42     }
  43
  44
  45     int arg = 0;
  46     for (arg = 1; arg < argc; arg++)
  47     {
  48         if (strcmp(argv[arg], "--help") == 0 && argc == 2) {
  49             usage(argv[0]);
  50         } else if (strcmp(argv[arg], "--version") == 0 && argc == 2) {
  51             printf("cat (mutos) v"VERSION"\n");
  52             return 0;
  53         } else if (strcmp(argv[arg], "--") == 0) { // the next args will be the actual args
  54             arg++;                                 // jump to first actual args
  55             break;                                 // and break out of flag loop
  56         } else {
  57             // done parsing flags
  58             break;
  59         }
  60     }
  61
  62     for (; arg < argc; arg++)
  63     {
  64         FILE *current_file = NULL;
  65
  66         if (strcmp(argv[arg], "-") == 0) {
  67             current_file = stdin;
  68         } else {
  69             current_file = fopen(argv[arg], "r");
  70         }
  71
  72
  73         if (current_file) {
  74             int c = fgetc(current_file);
  75             while (c != EOF)
  76             {
  77                 printf("%c", c);
  78                 c = fgetc(current_file);
  79             }
  80             fclose(current_file);
  81         } else {
  82             fprintf(stderr, "%s: %s: %s\n", argv[0], argv[arg], strerror(errno));
  83         }
  84     }
  85
  86     return 0;
  87 }