1 /* $NetBSD: head.c,v 1.17 2004/01/05 23:23:34 jmmv Exp $ */ 2 3 /* 4 * Copyright (c) 1980, 1987, 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 __COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1992, 1993\n\ 35 The Regents of the University of California. All rights reserved.\n"); 36 #endif /* not lint */ 37 38 #ifndef lint 39 #if 0 40 static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; 41 #else 42 __RCSID("$NetBSD: head.c,v 1.17 2004/01/05 23:23:34 jmmv Exp $"); 43 #endif 44 #endif /* not lint */ 45 46 #include <sys/types.h> 47 48 #include <ctype.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <limits.h> 52 #include <locale.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 /* 59 * head - give the first few lines of a stream or of each of a set of files 60 * 61 * Bill Joy UCB August 24, 1977 62 */ 63 64 void head __P((FILE *, long)); 65 void obsolete __P((char *[])); 66 void usage __P((void)); 67 int main __P((int, char *[])); 68 69 int eval = 0; 70 71 int 72 main(argc, argv) 73 int argc; 74 char *argv[]; 75 { 76 int ch; 77 FILE *fp; 78 int first; 79 long linecnt; 80 char *ep; 81 82 (void)setlocale(LC_ALL, ""); 83 obsolete(argv); 84 linecnt = 10; 85 while ((ch = getopt(argc, argv, "n:")) != -1) 86 switch(ch) { 87 case 'n': 88 errno = 0; 89 linecnt = strtol(optarg, &ep, 10); 90 if ((linecnt == LONG_MIN || linecnt == LONG_MAX) && 91 errno == ERANGE) 92 err(1, "illegal line count -- %s", optarg); 93 else if (*ep || linecnt <= 0) 94 errx(1, "illegal line count -- %s", optarg); 95 break; 96 97 case '?': 98 default: 99 usage(); 100 } 101 argc -= optind; 102 argv += optind; 103 104 if (*argv) 105 for (first = 1; *argv; ++argv) { 106 if ((fp = fopen(*argv, "r")) == NULL) { 107 warn("%s", *argv); 108 eval = 1; 109 continue; 110 } 111 if (argc > 1) { 112 (void)printf("%s==> %s <==\n", 113 first ? "" : "\n", *argv); 114 first = 0; 115 } 116 head(fp, linecnt); 117 (void)fclose(fp); 118 } 119 else 120 head(stdin, linecnt); 121 exit(eval); 122 } 123 124 void 125 head(fp, cnt) 126 FILE *fp; 127 long cnt; 128 { 129 int ch; 130 131 while (cnt--) 132 while ((ch = getc(fp)) != EOF) { 133 if (putchar(ch) == EOF) 134 err(1, "stdout"); 135 if (ch == '\n') 136 break; 137 } 138 } 139 140 void 141 obsolete(argv) 142 char *argv[]; 143 { 144 char *ap; 145 146 while ((ap = *++argv)) { 147 /* Return if "--" or not "-[0-9]*". */ 148 if (ap[0] != '-' || ap[1] == '-' || 149 !isdigit((unsigned char)ap[1])) 150 return; 151 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 152 err(1, NULL); 153 ap[0] = '-'; 154 ap[1] = 'n'; 155 (void)strcpy(ap + 2, *argv + 1); 156 *argv = ap; 157 } 158 } 159 160 void 161 usage() 162 { 163 164 (void)fprintf(stderr, "usage: %s [-n lines] [file ...]\n", 165 getprogname()); 166 exit(1); 167 } 168