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 "$FreeBSD$"; 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 eval; 69 70 int 71 main(argc, argv) 72 int argc; 73 char *argv[]; 74 { 75 register int ch; 76 FILE *fp; 77 int first, linecnt = -1, bytecnt = -1; 78 char *ep; 79 80 obsolete(argv); 81 while ((ch = getopt(argc, argv, "n:c:")) != -1) 82 switch(ch) { 83 case 'c': 84 bytecnt = strtol(optarg, &ep, 10); 85 if (*ep || bytecnt <= 0) 86 errx(1, "illegal byte count -- %s", optarg); 87 break; 88 case 'n': 89 linecnt = strtol(optarg, &ep, 10); 90 if (*ep || linecnt <= 0) 91 errx(1, "illegal line count -- %s", optarg); 92 break; 93 case '?': 94 default: 95 usage(); 96 } 97 argc -= optind; 98 argv += optind; 99 100 if (linecnt != -1 && bytecnt != -1) 101 errx(1, "can't combine line and byte counts"); 102 if (linecnt == -1 ) 103 linecnt = 10; 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 if (bytecnt == -1) 117 head(fp, linecnt); 118 else 119 head_bytes(fp, bytecnt); 120 (void)fclose(fp); 121 } 122 } 123 else if (bytecnt == -1) 124 head(stdin, linecnt); 125 else 126 head_bytes(stdin, bytecnt); 127 128 exit(eval); 129 } 130 131 void 132 head(fp, cnt) 133 FILE *fp; 134 register int cnt; 135 { 136 register int ch; 137 138 while (cnt && (ch = getc(fp)) != EOF) { 139 if (putchar(ch) == EOF) 140 err(1, "stdout"); 141 if (ch == '\n') 142 cnt--; 143 } 144 } 145 146 void 147 head_bytes(fp, cnt) 148 FILE *fp; 149 register int cnt; 150 { 151 char buf[4096]; 152 register int readlen; 153 154 while (cnt) { 155 if (cnt < sizeof(buf)) 156 readlen = cnt; 157 else 158 readlen = sizeof(buf); 159 readlen = fread(buf, sizeof(char), readlen, fp); 160 if (readlen == 0) 161 break; 162 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 163 err(1, "stdout"); 164 cnt -= readlen; 165 } 166 } 167 168 void 169 obsolete(argv) 170 char *argv[]; 171 { 172 char *ap; 173 174 while ((ap = *++argv)) { 175 /* Return if "--" or not "-[0-9]*". */ 176 if (ap[0] != '-' || ap[1] == '-' || !isdigit(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 (void)fprintf(stderr, "usage: head [-n lines] [-c bytes] [file ...]\n"); 191 exit(1); 192 } 193