1 /* $NetBSD: head.c,v 1.8 1997/10/19 02:23:45 lukem 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 __COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1992, 1993\n\ 39 The Regents of the University of California. All rights reserved.\n"); 40 #endif /* not lint */ 41 42 #ifndef lint 43 #if 0 44 static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; 45 #else 46 __RCSID("$NetBSD: head.c,v 1.8 1997/10/19 02:23:45 lukem Exp $"); 47 #endif 48 #endif /* not lint */ 49 50 #include <sys/types.h> 51 52 #include <ctype.h> 53 #include <err.h> 54 #include <errno.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 /* 61 * head - give the first few lines of a stream or of each of a set of files 62 * 63 * Bill Joy UCB August 24, 1977 64 */ 65 66 void head __P((FILE *, int)); 67 void obsolete __P((char *[])); 68 void usage __P((void)); 69 int main __P((int, char *[])); 70 71 int eval; 72 73 int 74 main(argc, argv) 75 int argc; 76 char *argv[]; 77 { 78 int ch; 79 FILE *fp; 80 int first, linecnt; 81 char *ep; 82 83 obsolete(argv); 84 linecnt = 10; 85 while ((ch = getopt(argc, argv, "n:")) != -1) 86 switch(ch) { 87 case 'n': 88 linecnt = strtol(optarg, &ep, 10); 89 if (*ep || linecnt <= 0) 90 err(1, "illegal line count -- %s", optarg); 91 break; 92 93 case '?': 94 default: 95 usage(); 96 } 97 argc -= optind; 98 argv += optind; 99 100 if (*argv) 101 for (first = 1; *argv; ++argv) { 102 if ((fp = fopen(*argv, "r")) == NULL) { 103 err(0, "%s: %s", *argv, strerror(errno)); 104 continue; 105 } 106 if (argc > 1) { 107 (void)printf("%s==> %s <==\n", 108 first ? "" : "\n", *argv); 109 first = 0; 110 } 111 head(fp, linecnt); 112 (void)fclose(fp); 113 } 114 else 115 head(stdin, linecnt); 116 exit(eval); 117 } 118 119 void 120 head(fp, cnt) 121 FILE *fp; 122 int cnt; 123 { 124 int ch; 125 126 while (cnt--) 127 while ((ch = getc(fp)) != EOF) { 128 if (putchar(ch) == EOF) 129 err(1, "stdout: %s", strerror(errno)); 130 if (ch == '\n') 131 break; 132 } 133 } 134 135 void 136 obsolete(argv) 137 char *argv[]; 138 { 139 char *ap; 140 141 while ((ap = *++argv)) { 142 /* Return if "--" or not "-[0-9]*". */ 143 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 144 return; 145 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 146 err(1, "%s", strerror(errno)); 147 ap[0] = '-'; 148 ap[1] = 'n'; 149 (void)strcpy(ap + 2, *argv + 1); 150 *argv = ap; 151 } 152 } 153 154 void 155 usage() 156 { 157 (void)fputs("usage: head [-n lines] [file ...]\n", stderr); 158 exit(1); 159 } 160