1 /* 2 * Copyright (c) 1980, 1987, 1992, 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 * @(#) Copyright (c) 1980, 1987, 1992, 1993 The Regents of the University of California. All rights reserved. 34 * @(#)head.c 8.2 (Berkeley) 5/4/95 35 * $FreeBSD: src/usr.bin/head/head.c,v 1.10.2.1 2002/02/16 12:29:04 dwmalone Exp $ 36 * $DragonFly: src/usr.bin/head/head.c,v 1.3 2003/10/04 20:36:45 hmp Exp $ 37 */ 38 39 #include <sys/types.h> 40 41 #include <ctype.h> 42 #include <err.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <unistd.h> 47 48 /* 49 * head - give the first few lines of a stream or of each of a set of files 50 * 51 * Bill Joy UCB August 24, 1977 52 */ 53 54 void head(FILE *, int); 55 void head_bytes(FILE *, int); 56 void obsolete(char *[]); 57 void usage(void); 58 59 int 60 main(int argc, char **argv) 61 { 62 register int ch; 63 FILE *fp; 64 int first, linecnt = -1, bytecnt = -1, eval = 0; 65 char *ep; 66 67 obsolete(argv); 68 while ((ch = getopt(argc, argv, "n:c:")) != -1) 69 switch(ch) { 70 case 'c': 71 bytecnt = strtol(optarg, &ep, 10); 72 if (*ep || bytecnt <= 0) 73 errx(1, "illegal byte count -- %s", optarg); 74 break; 75 case 'n': 76 linecnt = strtol(optarg, &ep, 10); 77 if (*ep || linecnt <= 0) 78 errx(1, "illegal line count -- %s", optarg); 79 break; 80 case '?': 81 default: 82 usage(); 83 } 84 argc -= optind; 85 argv += optind; 86 87 if (linecnt != -1 && bytecnt != -1) 88 errx(1, "can't combine line and byte counts"); 89 if (linecnt == -1 ) 90 linecnt = 10; 91 if (*argv) { 92 for (first = 1; *argv; ++argv) { 93 if ((fp = fopen(*argv, "r")) == NULL) { 94 warn("%s", *argv); 95 eval = 1; 96 continue; 97 } 98 if (argc > 1) { 99 (void)printf("%s==> %s <==\n", 100 first ? "" : "\n", *argv); 101 first = 0; 102 } 103 if (bytecnt == -1) 104 head(fp, linecnt); 105 else 106 head_bytes(fp, bytecnt); 107 (void)fclose(fp); 108 } 109 } else if (bytecnt == -1) 110 head(stdin, linecnt); 111 else 112 head_bytes(stdin, bytecnt); 113 114 exit(eval); 115 } 116 117 void 118 head(FILE *fp, register int cnt) 119 { 120 char *cp; 121 int error, readlen; 122 123 while (cnt && (cp = fgetln(fp, &readlen)) != NULL) { 124 error = fwrite(cp, sizeof(char), readlen, stdout); 125 if (error != readlen) 126 err(1, "stdout"); 127 cnt--; 128 } 129 } 130 131 void 132 head_bytes(FILE *fp, register int cnt) 133 { 134 char buf[4096]; 135 register int readlen; 136 137 while (cnt) { 138 if (cnt < sizeof(buf)) 139 readlen = cnt; 140 else 141 readlen = sizeof(buf); 142 readlen = fread(buf, sizeof(char), readlen, fp); 143 if (readlen == 0) 144 break; 145 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 146 err(1, "stdout"); 147 cnt -= readlen; 148 } 149 } 150 151 void 152 obsolete(char **argv) 153 { 154 char *ap; 155 156 while ((ap = *++argv)) { 157 /* Return if "--" or not "-[0-9]*". */ 158 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 159 return; 160 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 161 err(1, NULL); 162 ap[0] = '-'; 163 ap[1] = 'n'; 164 (void)strcpy(ap + 2, *argv + 1); 165 *argv = ap; 166 } 167 } 168 169 void 170 usage(void) 171 { 172 173 (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 174 exit(1); 175 } 176