1 /* $NetBSD: head.c,v 1.18 2004/05/04 10:57:42 mrg 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 1.18 2004/05/04 10:57:42 mrg 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, 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 long bytecnt; 81 char *ep; 82 int qflag = 0; 83 int vflag = 0; 84 85 (void)setlocale(LC_ALL, ""); 86 obsolete(argv); 87 linecnt = 10; 88 bytecnt = 0; 89 while ((ch = getopt(argc, argv, "c:n:qv")) != -1) 90 switch(ch) { 91 case 'c': 92 errno = 0; 93 bytecnt = strtol(optarg, &ep, 10); 94 if ((bytecnt == LONG_MIN || bytecnt == LONG_MAX) && 95 errno == ERANGE) 96 err(1, "illegal byte count -- %s", optarg); 97 else if (*ep || bytecnt <= 0) 98 errx(1, "illegal byte count -- %s", optarg); 99 break; 100 101 case 'n': 102 errno = 0; 103 linecnt = strtol(optarg, &ep, 10); 104 if ((linecnt == LONG_MIN || linecnt == LONG_MAX) && 105 errno == ERANGE) 106 err(1, "illegal line count -- %s", optarg); 107 else if (*ep || linecnt <= 0) 108 errx(1, "illegal line count -- %s", optarg); 109 break; 110 111 case 'q': 112 qflag = 1; 113 vflag = 0; 114 break; 115 116 case 'v': 117 qflag = 0; 118 vflag = 1; 119 break; 120 121 case '?': 122 default: 123 usage(); 124 } 125 argc -= optind; 126 argv += optind; 127 128 if (*argv) 129 for (first = 1; *argv; ++argv) { 130 if ((fp = fopen(*argv, "r")) == NULL) { 131 warn("%s", *argv); 132 eval = 1; 133 continue; 134 } 135 if (vflag || (qflag == 0 && argc > 1)) { 136 (void)printf("%s==> %s <==\n", 137 first ? "" : "\n", *argv); 138 first = 0; 139 } 140 head(fp, linecnt, bytecnt); 141 (void)fclose(fp); 142 } 143 else 144 head(stdin, linecnt, bytecnt); 145 exit(eval); 146 } 147 148 void 149 head(fp, cnt, bytecnt) 150 FILE *fp; 151 long cnt; 152 long bytecnt; 153 { 154 int ch; 155 156 if (bytecnt) 157 cnt = bytecnt; 158 while (cnt--) 159 while ((ch = getc(fp)) != EOF) { 160 if (putchar(ch) == EOF) 161 err(1, "stdout"); 162 if (ch == '\n' || bytecnt) 163 break; 164 } 165 } 166 167 void 168 obsolete(argv) 169 char *argv[]; 170 { 171 char *ap; 172 173 while ((ap = *++argv)) { 174 /* Return if "--" or not "-[0-9]*". */ 175 if (ap[0] != '-' || ap[1] == '-' || 176 !isdigit((unsigned char)ap[1])) 177 return; 178 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 179 err(1, NULL); 180 ap[0] = '-'; 181 ap[1] = 'n'; 182 (void)strcpy(ap + 2, *argv + 1); 183 *argv = ap; 184 } 185 } 186 187 void 188 usage() 189 { 190 191 (void)fprintf(stderr, "usage: %s [-n lines] [file ...]\n", 192 getprogname()); 193 exit(1); 194 } 195