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 61int 62main(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