commands/simple/rev.c

   1 /*-
   2  * Copyright (c) 1987, 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifndef lint
  35 static const char copyright[] =
  36 "@(#) Copyright (c) 1987, 1992, 1993\n\
  37         The Regents of the University of California.  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 #include <sys/types.h>
  41
  42 #include <errno.h>
  43 #include <locale.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48
  49 void usage(void);
  50
  51 int
  52 main(int argc, char *argv[])
  53 {
  54         const char *filename;
  55         char p[2000], *t;
  56         FILE *fp;
  57         size_t len;
  58         int ch, rval;
  59
  60         setlocale(LC_ALL, "");
  61
  62         while ((ch = getopt(argc, argv, "")) != -1)
  63                 switch(ch) {
  64                 case '?':
  65                 default:
  66                         usage();
  67                 }
  68
  69         argc -= optind;
  70         argv += optind;
  71
  72         fp = stdin;
  73         filename = "stdin";
  74         rval = 0;
  75         do {
  76                 if (*argv) {
  77                         if ((fp = fopen(*argv, "r")) == NULL) {
  78                                 perror(*argv);
  79                                 rval = 1;
  80                                 ++argv;
  81                                 continue;
  82                         }
  83                         filename = *argv++;
  84                 }
  85                 while ((fgets(p, sizeof(p)-1, fp)) != NULL) {
  86                         len = strlen(p);
  87                         if (p[len - 1] == '\n')
  88                                 --len;
  89                         t = p + len - 1;
  90                         for (t = p + len - 1; t >= p; --t)
  91                                 putchar(*t);
  92                         putchar('\n');
  93                 }
  94                 if (ferror(fp)) {
  95                         perror(filename);
  96                         rval = 1;
  97                 }
  98                 (void)fclose(fp);
  99         } while(*argv);
 100         exit(rval);
 101 }
 102
 103 void
 104 usage(void)
 105 {
 106         (void)fprintf(stderr, "usage: rev [file ...]\n");
 107         exit(1);
 108 }