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 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 static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; 42 #endif /* not lint */ 43 44 #include <sys/types.h> 45 46 #include <ctype.h> 47 #include <errno.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <unistd.h> 52 53 /* 54 * head - give the first few lines of a stream or of each of a set of files 55 * 56 * Bill Joy UCB August 24, 1977 57 */ 58 59 void err __P((int, const char *, ...)); 60 void head __P((FILE *, int)); 61 void head_bytes __P((FILE *, int)); 62 void obsolete __P((char *[])); 63 void usage __P((void)); 64 65 int eval; 66 67 int 68 main(argc, argv) 69 int argc; 70 char *argv[]; 71 { 72 register int ch; 73 FILE *fp; 74 int first, linecnt = -1, bytecnt = -1; 75 char *ep; 76 77 obsolete(argv); 78 while ((ch = getopt(argc, argv, "n:c:")) != -1) 79 switch(ch) { 80 case 'c': 81 bytecnt = strtol(optarg, &ep, 10); 82 if (*ep || bytecnt <= 0) 83 err(1, "illegal byte count -- %s", optarg); 84 break; 85 case 'n': 86 linecnt = strtol(optarg, &ep, 10); 87 if (*ep || linecnt <= 0) 88 err(1, "illegal line count -- %s", optarg); 89 break; 90 case '?': 91 default: 92 usage(); 93 } 94 argc -= optind; 95 argv += optind; 96 97 if (linecnt != -1 && bytecnt != -1) 98 err(1, "can't combine line and byte counts"); 99 if (linecnt == -1 ) 100 linecnt = 10; 101 if (*argv) { 102 for (first = 1; *argv; ++argv) { 103 if ((fp = fopen(*argv, "r")) == NULL) { 104 err(0, "%s: %s", *argv, strerror(errno)); 105 continue; 106 } 107 if (argc > 1) { 108 (void)printf("%s==> %s <==\n", 109 first ? "" : "\n", *argv); 110 first = 0; 111 } 112 if (bytecnt == -1) 113 head(fp, linecnt); 114 else 115 head_bytes(fp, bytecnt); 116 (void)fclose(fp); 117 } 118 } 119 else if (bytecnt == -1) 120 head(stdin, linecnt); 121 else 122 head_bytes(stdin, bytecnt); 123 124 exit(eval); 125 } 126 127 void 128 head(fp, cnt) 129 FILE *fp; 130 register int cnt; 131 { 132 register int ch; 133 134 while (cnt && (ch = getc(fp)) != EOF) { 135 if (putchar(ch) == EOF) 136 err(1, "stdout: %s", strerror(errno)); 137 if (ch == '\n') 138 cnt--; 139 } 140 } 141 142 void 143 head_bytes(fp, cnt) 144 FILE *fp; 145 register int cnt; 146 { 147 char buf[4096]; 148 register int readlen; 149 150 while (cnt) { 151 if (cnt < sizeof(buf)) 152 readlen = cnt; 153 else 154 readlen = sizeof(buf); 155 readlen = fread(buf, sizeof(char), readlen, fp); 156 if (readlen == EOF) 157 break; 158 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 159 err(1, "stdout: %s", strerror(errno)); 160 cnt -= readlen; 161 } 162 } 163 164 void 165 obsolete(argv) 166 char *argv[]; 167 { 168 char *ap; 169 170 while ((ap = *++argv)) { 171 /* Return if "--" or not "-[0-9]*". */ 172 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 173 return; 174 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 175 err(1, "%s", strerror(errno)); 176 ap[0] = '-'; 177 ap[1] = 'n'; 178 (void)strcpy(ap + 2, *argv + 1); 179 *argv = ap; 180 } 181 } 182 183 void 184 usage() 185 { 186 (void)fprintf(stderr, "usage: head [-n lines] [file ...]\n"); 187 exit(1); 188 } 189 190 #if __STDC__ 191 #include <stdarg.h> 192 #else 193 #include <varargs.h> 194 #endif 195 196 void 197 #if __STDC__ 198 err(int fatal, const char *fmt, ...) 199 #else 200 err(fatal, fmt, va_alist) 201 int fatal; 202 char *fmt; 203 va_dcl 204 #endif 205 { 206 va_list ap; 207 #if __STDC__ 208 va_start(ap, fmt); 209 #else 210 va_start(ap); 211 #endif 212 (void)fprintf(stderr, "head: "); 213 (void)vfprintf(stderr, fmt, ap); 214 va_end(ap); 215 (void)fprintf(stderr, "\n"); 216 if (fatal) 217 exit(1); 218 eval = 1; 219 } 220