head.c revision 95652
11590Srgrimes/* 21590Srgrimes * Copyright (c) 1980, 1987, 1992, 1993 31590Srgrimes * The Regents of the University of California. All rights reserved. 41590Srgrimes * 51590Srgrimes * Redistribution and use in source and binary forms, with or without 61590Srgrimes * modification, are permitted provided that the following conditions 71590Srgrimes * are met: 81590Srgrimes * 1. Redistributions of source code must retain the above copyright 91590Srgrimes * notice, this list of conditions and the following disclaimer. 101590Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111590Srgrimes * notice, this list of conditions and the following disclaimer in the 121590Srgrimes * documentation and/or other materials provided with the distribution. 131590Srgrimes * 3. All advertising materials mentioning features or use of this software 141590Srgrimes * must display the following acknowledgement: 151590Srgrimes * This product includes software developed by the University of 161590Srgrimes * California, Berkeley and its contributors. 171590Srgrimes * 4. Neither the name of the University nor the names of its contributors 181590Srgrimes * may be used to endorse or promote products derived from this software 191590Srgrimes * without specific prior written permission. 201590Srgrimes * 211590Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221590Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231590Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241590Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251590Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261590Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271590Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281590Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291590Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301590Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311590Srgrimes * SUCH DAMAGE. 321590Srgrimes */ 331590Srgrimes 341590Srgrimes#ifndef lint 3527314Scharnierstatic const char copyright[] = 361590Srgrimes"@(#) Copyright (c) 1980, 1987, 1992, 1993\n\ 371590Srgrimes The Regents of the University of California. All rights reserved.\n"; 381590Srgrimes#endif /* not lint */ 391590Srgrimes 401590Srgrimes#ifndef lint 4127314Scharnier#if 0 4223693Speterstatic char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; 4327314Scharnier#endif 441590Srgrimes#endif /* not lint */ 451590Srgrimes 4695652Smarkm#include <sys/cdefs.h> 4795652Smarkm__FBSDID("$FreeBSD: head/usr.bin/head/head.c 95652 2002-04-28 13:50:54Z markm $"); 4895652Smarkm 491590Srgrimes#include <sys/types.h> 5023693Speter 5123693Speter#include <ctype.h> 5227314Scharnier#include <err.h> 5323693Speter#include <stdio.h> 541590Srgrimes#include <stdlib.h> 551590Srgrimes#include <string.h> 5623693Speter#include <unistd.h> 571590Srgrimes 581590Srgrimes/* 591590Srgrimes * head - give the first few lines of a stream or of each of a set of files 601590Srgrimes * 611590Srgrimes * Bill Joy UCB August 24, 1977 621590Srgrimes */ 631590Srgrimes 6493441Sdwmalonestatic void head(FILE *, int); 6593441Sdwmalonestatic void head_bytes(FILE *, size_t); 6693441Sdwmalonestatic void obsolete(char *[]); 6793441Sdwmalonestatic void usage(void); 681590Srgrimes 691590Srgrimesint 7095652Smarkmmain(int argc, char *argv[]) 711590Srgrimes{ 7293441Sdwmalone int ch; 731590Srgrimes FILE *fp; 7485859Salfred int first, linecnt = -1, bytecnt = -1, eval = 0; 751590Srgrimes char *ep; 761590Srgrimes 771590Srgrimes obsolete(argv); 7824665Salex while ((ch = getopt(argc, argv, "n:c:")) != -1) 791590Srgrimes switch(ch) { 8024665Salex case 'c': 8124665Salex bytecnt = strtol(optarg, &ep, 10); 8224665Salex if (*ep || bytecnt <= 0) 8327314Scharnier errx(1, "illegal byte count -- %s", optarg); 8424665Salex break; 851590Srgrimes case 'n': 861590Srgrimes linecnt = strtol(optarg, &ep, 10); 871590Srgrimes if (*ep || linecnt <= 0) 8827314Scharnier errx(1, "illegal line count -- %s", optarg); 891590Srgrimes break; 901590Srgrimes case '?': 911590Srgrimes default: 921590Srgrimes usage(); 931590Srgrimes } 941590Srgrimes argc -= optind; 951590Srgrimes argv += optind; 961590Srgrimes 9724665Salex if (linecnt != -1 && bytecnt != -1) 9827314Scharnier errx(1, "can't combine line and byte counts"); 9924665Salex if (linecnt == -1 ) 10024665Salex linecnt = 10; 10124665Salex if (*argv) { 1021590Srgrimes for (first = 1; *argv; ++argv) { 1031590Srgrimes if ((fp = fopen(*argv, "r")) == NULL) { 10427314Scharnier warn("%s", *argv); 10527328Scharnier eval = 1; 1061590Srgrimes continue; 1071590Srgrimes } 1081590Srgrimes if (argc > 1) { 1091590Srgrimes (void)printf("%s==> %s <==\n", 1101590Srgrimes first ? "" : "\n", *argv); 1111590Srgrimes first = 0; 1121590Srgrimes } 11324665Salex if (bytecnt == -1) 11424665Salex head(fp, linecnt); 11524665Salex else 11624665Salex head_bytes(fp, bytecnt); 1171590Srgrimes (void)fclose(fp); 1181590Srgrimes } 11985859Salfred } else if (bytecnt == -1) 12024665Salex head(stdin, linecnt); 1211590Srgrimes else 12224665Salex head_bytes(stdin, bytecnt); 12324665Salex 1241590Srgrimes exit(eval); 1251590Srgrimes} 1261590Srgrimes 12793441Sdwmalonestatic void 12895652Smarkmhead(FILE *fp, int cnt) 1291590Srgrimes{ 13085861Salfred char *cp; 13193441Sdwmalone size_t error, readlen; 1321590Srgrimes 13385861Salfred while (cnt && (cp = fgetln(fp, &readlen)) != NULL) { 13485861Salfred error = fwrite(cp, sizeof(char), readlen, stdout); 13585861Salfred if (error != readlen) 13685861Salfred err(1, "stdout"); 13785861Salfred cnt--; 13885861Salfred } 1391590Srgrimes} 1401590Srgrimes 14193441Sdwmalonestatic void 14295652Smarkmhead_bytes(FILE *fp, size_t cnt) 14324665Salex{ 14424665Salex char buf[4096]; 14593441Sdwmalone size_t readlen; 14624665Salex 14724665Salex while (cnt) { 14824665Salex if (cnt < sizeof(buf)) 14924665Salex readlen = cnt; 15024665Salex else 15124665Salex readlen = sizeof(buf); 15224665Salex readlen = fread(buf, sizeof(char), readlen, fp); 15340114Sdes if (readlen == 0) 15424665Salex break; 15524665Salex if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 15627314Scharnier err(1, "stdout"); 15724665Salex cnt -= readlen; 15824665Salex } 15924665Salex} 16024665Salex 16193441Sdwmalonestatic void 16295652Smarkmobsolete(char *argv[]) 1631590Srgrimes{ 1641590Srgrimes char *ap; 1651590Srgrimes 16624665Salex while ((ap = *++argv)) { 1671590Srgrimes /* Return if "--" or not "-[0-9]*". */ 1681590Srgrimes if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 1691590Srgrimes return; 1701590Srgrimes if ((ap = malloc(strlen(*argv) + 2)) == NULL) 17127314Scharnier err(1, NULL); 1721590Srgrimes ap[0] = '-'; 1731590Srgrimes ap[1] = 'n'; 1741590Srgrimes (void)strcpy(ap + 2, *argv + 1); 1751590Srgrimes *argv = ap; 1761590Srgrimes } 1771590Srgrimes} 1781590Srgrimes 17993441Sdwmalonestatic void 18095652Smarkmusage(void) 1811590Srgrimes{ 18285859Salfred 18389767Sdwmalone (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 1841590Srgrimes exit(1); 1851590Srgrimes} 186