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 34 #ifndef lint 35 static const char copyright[] = 36 "@(#) Copyright (c) 1980, 1987, 1992, 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[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; 43 #endif 44 static const char rcsid[] = 45 "$FreeBSD: src/usr.bin/head/head.c,v 1.10.2.1 2002/02/16 12:29:04 dwmalone Exp $"; 46 #endif /* not lint */ 47 48 #include <sys/types.h> 49 50 #include <ctype.h> 51 #include <err.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 /* 58 * head - give the first few lines of a stream or of each of a set of files 59 * 60 * Bill Joy UCB August 24, 1977 61 */ 62 63 void head __P((FILE *, int)); 64 void head_bytes __P((FILE *, int)); 65 void obsolete __P((char *[])); 66 void usage __P((void)); 67 68 int 69 main(argc, argv) 70 int argc; 71 char *argv[]; 72 { 73 register int ch; 74 FILE *fp; 75 int first, linecnt = -1, bytecnt = -1, eval = 0; 76 char *ep; 77 78 obsolete(argv); 79 while ((ch = getopt(argc, argv, "n:c:")) != -1) 80 switch(ch) { 81 case 'c': 82 bytecnt = strtol(optarg, &ep, 10); 83 if (*ep || bytecnt <= 0) 84 errx(1, "illegal byte count -- %s", optarg); 85 break; 86 case 'n': 87 linecnt = strtol(optarg, &ep, 10); 88 if (*ep || linecnt <= 0) 89 errx(1, "illegal line count -- %s", optarg); 90 break; 91 case '?': 92 default: 93 usage(); 94 } 95 argc -= optind; 96 argv += optind; 97 98 if (linecnt != -1 && bytecnt != -1) 99 errx(1, "can't combine line and byte counts"); 100 if (linecnt == -1 ) 101 linecnt = 10; 102 if (*argv) { 103 for (first = 1; *argv; ++argv) { 104 if ((fp = fopen(*argv, "r")) == NULL) { 105 warn("%s", *argv); 106 eval = 1; 107 continue; 108 } 109 if (argc > 1) { 110 (void)printf("%s==> %s <==\n", 111 first ? "" : "\n", *argv); 112 first = 0; 113 } 114 if (bytecnt == -1) 115 head(fp, linecnt); 116 else 117 head_bytes(fp, bytecnt); 118 (void)fclose(fp); 119 } 120 } else if (bytecnt == -1) 121 head(stdin, linecnt); 122 else 123 head_bytes(stdin, bytecnt); 124 125 exit(eval); 126 } 127 128 void 129 head(fp, cnt) 130 FILE *fp; 131 register int cnt; 132 { 133 char *cp; 134 int error, readlen; 135 136 while (cnt && (cp = fgetln(fp, &readlen)) != NULL) { 137 error = fwrite(cp, sizeof(char), readlen, stdout); 138 if (error != readlen) 139 err(1, "stdout"); 140 cnt--; 141 } 142 } 143 144 void 145 head_bytes(fp, cnt) 146 FILE *fp; 147 register int cnt; 148 { 149 char buf[4096]; 150 register int readlen; 151 152 while (cnt) { 153 if (cnt < sizeof(buf)) 154 readlen = cnt; 155 else 156 readlen = sizeof(buf); 157 readlen = fread(buf, sizeof(char), readlen, fp); 158 if (readlen == 0) 159 break; 160 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 161 err(1, "stdout"); 162 cnt -= readlen; 163 } 164 } 165 166 void 167 obsolete(argv) 168 char *argv[]; 169 { 170 char *ap; 171 172 while ((ap = *++argv)) { 173 /* Return if "--" or not "-[0-9]*". */ 174 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 175 return; 176 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 177 err(1, NULL); 178 ap[0] = '-'; 179 ap[1] = 'n'; 180 (void)strcpy(ap + 2, *argv + 1); 181 *argv = ap; 182 } 183 } 184 185 void 186 usage() 187 { 188 189 (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 190 exit(1); 191 } 192