bin/sh/bltin/echo.c

   1 /*      $NetBSD: echo.c,v 1.13 2007/12/12 22:55:43 lukem Exp $  */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Kenneth Almquist.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)echo.c      8.1 (Berkeley) 5/31/93
  35  */
  36
  37 /*
  38  * Echo command.
  39  *
  40  * echo is steeped in tradition - several of them!
  41  * netbsd has supported 'echo [-n | -e] args' in spite of -e not being
  42  * documented anywhere.
  43  * Posix requires that -n be supported, output from strings containing
  44  * \ is implementation defined
  45  * The Single Unix Spec requires that \ escapes be treated as if -e
  46  * were set, but that -n not be treated as an option.
  47  * (ksh supports 'echo [-eEn] args', but not -- so that it is actually
  48  * impossible to actually output '-n')
  49  *
  50  * It is suggested that 'printf "%b" "string"' be used to get \ sequences
  51  * expanded.  printf is now a builtin of netbsd's sh and csh.
  52  */
  53
  54 #include <sys/cdefs.h>
  55 __RCSID("$NetBSD: echo.c,v 1.13 2007/12/12 22:55:43 lukem Exp $");
  56
  57 #define main echocmd
  58
  59 #include "bltin.h"
  60
  61 int
  62 main(int argc, char **argv)
  63 {
  64         char **ap;
  65         char *p;
  66         char c;
  67         int count;
  68         int nflag = 0;
  69         int eflag = 0;
  70
  71         ap = argv;
  72         if (argc)
  73                 ap++;
  74
  75         if ((p = *ap) != NULL) {
  76                 if (equal(p, "-n")) {
  77                         nflag = 1;
  78                         ap++;
  79                 } else if (equal(p, "-e")) {
  80                         eflag = 1;
  81                         ap++;
  82                 }
  83         }
  84
  85         while ((p = *ap++) != NULL) {
  86                 while ((c = *p++) != '\0') {
  87                         if (c == '\\' && eflag) {
  88                                 switch (*p++) {
  89                                 case 'a':  c = '\a';  break;    /* bell */
  90                                 case 'b':  c = '\b';  break;
  91                                 case 'c':  return 0;            /* exit */
  92                                 case 'e':  c =  033;  break;    /* escape */
  93                                 case 'f':  c = '\f';  break;
  94                                 case 'n':  c = '\n';  break;
  95                                 case 'r':  c = '\r';  break;
  96                                 case 't':  c = '\t';  break;
  97                                 case 'v':  c = '\v';  break;
  98                                 case '\\':  break;              /* c = '\\' */
  99                                 case '0':
 100                                         c = 0;
 101                                         count = 3;
 102                                         while (--count >= 0 && (unsigned)(*p - '0') < 8)
 103                                                 c = (c << 3) + (*p++ - '0');
 104                                         break;
 105                                 default:
 106                                         /* Output the '/' and char following */
 107                                         p--;
 108                                         break;
 109                                 }
 110                         }
 111                         putchar(c);
 112                 }
 113                 if (*ap)
 114                         putchar(' ');
 115         }
 116         if (! nflag)
 117                 putchar('\n');
 118         fflush(stdout);
 119         if (ferror(stdout))
 120                 return 1;
 121         return 0;
 122 }