xref: /freebsd/bin/echo/echo.c (revision c17d43407fe04133a94055b0dbc7ea8965654a9f)
1 /*
2  * Copyright (c) 1989, 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 char const copyright[] =
36 "@(#) Copyright (c) 1989, 1993\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)echo.c	8.1 (Berkeley) 5/31/93";
43 #endif
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif /* not lint */
47 
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 
52 /* ARGSUSED */
53 int
54 main(int argc __unused, char *argv[])
55 {
56 	int nflag;	/* if not set, output a trailing newline. */
57 
58 	/* This utility may NOT do getopt(3) option parsing. */
59 	if (*++argv && !strcmp(*argv, "-n")) {
60 		++argv;
61 		nflag = 1;
62 	}
63 	else
64 		nflag = 0;
65 
66 	while (argv[0] != NULL) {
67 
68 		/*
69 		 * If the next argument is NULL then this is this
70 		 * the last argument, therefore we need to check
71 		 * for a trailing \c.
72 		 */
73 		if (argv[1] == NULL) {
74 			size_t len;
75 
76 			len = strlen(argv[0]);
77 			/* is there room for a '\c' and is there one? */
78 			if (len >= 2 &&
79 			    argv[0][len - 2] == '\\' &&
80 			    argv[0][len - 1] == 'c') {
81 				/* chop it and set the no-newline flag. */
82 				argv[0][len - 2] = '\0';
83 				nflag = 1;
84 			}
85 		}
86 		(void)printf("%s", argv[0]);
87 		if (*++argv)
88 			putchar(' ');
89 	}
90 	if (!nflag)
91 		putchar('\n');
92 	return 0;
93 }
94