1 /* $NetBSD: echo.c,v 1.15 2021/05/18 21:39:06 kre 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 1.15 2021/05/18 21:39:06 kre Exp $");
56
57 #define main echocmd
58
59 #include "bltin.h"
60
61 int
main(int argc,char ** argv)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 clearerr(stdout);
72
73 ap = argv;
74 if (argc)
75 ap++;
76
77 if ((p = *ap) != NULL) {
78 if (equal(p, "-n")) {
79 nflag = 1;
80 ap++;
81 } else if (equal(p, "-e")) {
82 eflag = 1;
83 ap++;
84 }
85 }
86
87 while ((p = *ap++) != NULL) {
88 while ((c = *p++) != '\0') {
89 if (c == '\\' && eflag) {
90 switch (*p++) {
91 case 'a': c = '\a'; break; /* bell */
92 case 'b': c = '\b'; break;
93 case 'c': return 0; /* exit */
94 case 'e': c = 033; break; /* escape */
95 case 'f': c = '\f'; break;
96 case 'n': c = '\n'; break;
97 case 'r': c = '\r'; break;
98 case 't': c = '\t'; break;
99 case 'v': c = '\v'; break;
100 case '\\': break; /* c = '\\' */
101 case '0':
102 c = 0;
103 count = 3;
104 while (--count >= 0 && (unsigned)(*p - '0') < 8)
105 c = (c << 3) + (*p++ - '0');
106 break;
107 default:
108 /* Output the '/' and char following */
109 p--;
110 break;
111 }
112 }
113 putchar(c);
114 }
115 if (*ap)
116 putchar(' ');
117 }
118 if (! nflag)
119 putchar('\n');
120 fflush(stdout);
121 if (ferror(stdout)) {
122 clearerr(stdout);
123 err(1, "write error");
124 }
125 return 0;
126 }
127