1 /* $NetBSD: echo.c,v 1.14 2008/10/12 01:40:37 dholland 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 1.14 2008/10/12 01:40:37 dholland 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 } 123