head.c revision 93441
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 4427314Scharnierstatic const char rcsid[] = 4550477Speter "$FreeBSD: head/usr.bin/head/head.c 93441 2002-03-30 17:17:26Z dwmalone $"; 461590Srgrimes#endif /* not lint */ 471590Srgrimes 481590Srgrimes#include <sys/types.h> 4923693Speter 5023693Speter#include <ctype.h> 5127314Scharnier#include <err.h> 5223693Speter#include <stdio.h> 531590Srgrimes#include <stdlib.h> 541590Srgrimes#include <string.h> 5523693Speter#include <unistd.h> 561590Srgrimes 571590Srgrimes/* 581590Srgrimes * head - give the first few lines of a stream or of each of a set of files 591590Srgrimes * 601590Srgrimes * Bill Joy UCB August 24, 1977 611590Srgrimes */ 621590Srgrimes 6393441Sdwmalonestatic void head(FILE *, int); 6493441Sdwmalonestatic void head_bytes(FILE *, size_t); 6593441Sdwmalonestatic void obsolete(char *[]); 6693441Sdwmalonestatic void usage(void); 671590Srgrimes 681590Srgrimesint 691590Srgrimesmain(argc, argv) 701590Srgrimes int argc; 711590Srgrimes char *argv[]; 721590Srgrimes{ 7393441Sdwmalone int ch; 741590Srgrimes FILE *fp; 7585859Salfred int first, linecnt = -1, bytecnt = -1, eval = 0; 761590Srgrimes char *ep; 771590Srgrimes 781590Srgrimes obsolete(argv); 7924665Salex while ((ch = getopt(argc, argv, "n:c:")) != -1) 801590Srgrimes switch(ch) { 8124665Salex case 'c': 8224665Salex bytecnt = strtol(optarg, &ep, 10); 8324665Salex if (*ep || bytecnt <= 0) 8427314Scharnier errx(1, "illegal byte count -- %s", optarg); 8524665Salex break; 861590Srgrimes case 'n': 871590Srgrimes linecnt = strtol(optarg, &ep, 10); 881590Srgrimes if (*ep || linecnt <= 0) 8927314Scharnier errx(1, "illegal line count -- %s", optarg); 901590Srgrimes break; 911590Srgrimes case '?': 921590Srgrimes default: 931590Srgrimes usage(); 941590Srgrimes } 951590Srgrimes argc -= optind; 961590Srgrimes argv += optind; 971590Srgrimes 9824665Salex if (linecnt != -1 && bytecnt != -1) 9927314Scharnier errx(1, "can't combine line and byte counts"); 10024665Salex if (linecnt == -1 ) 10124665Salex linecnt = 10; 10224665Salex if (*argv) { 1031590Srgrimes for (first = 1; *argv; ++argv) { 1041590Srgrimes if ((fp = fopen(*argv, "r")) == NULL) { 10527314Scharnier warn("%s", *argv); 10627328Scharnier eval = 1; 1071590Srgrimes continue; 1081590Srgrimes } 1091590Srgrimes if (argc > 1) { 1101590Srgrimes (void)printf("%s==> %s <==\n", 1111590Srgrimes first ? "" : "\n", *argv); 1121590Srgrimes first = 0; 1131590Srgrimes } 11424665Salex if (bytecnt == -1) 11524665Salex head(fp, linecnt); 11624665Salex else 11724665Salex head_bytes(fp, bytecnt); 1181590Srgrimes (void)fclose(fp); 1191590Srgrimes } 12085859Salfred } else if (bytecnt == -1) 12124665Salex head(stdin, linecnt); 1221590Srgrimes else 12324665Salex head_bytes(stdin, bytecnt); 12424665Salex 1251590Srgrimes exit(eval); 1261590Srgrimes} 1271590Srgrimes 12893441Sdwmalonestatic void 1291590Srgrimeshead(fp, cnt) 1301590Srgrimes FILE *fp; 13193441Sdwmalone int cnt; 1321590Srgrimes{ 13385861Salfred char *cp; 13493441Sdwmalone size_t error, readlen; 1351590Srgrimes 13685861Salfred while (cnt && (cp = fgetln(fp, &readlen)) != NULL) { 13785861Salfred error = fwrite(cp, sizeof(char), readlen, stdout); 13885861Salfred if (error != readlen) 13985861Salfred err(1, "stdout"); 14085861Salfred cnt--; 14185861Salfred } 1421590Srgrimes} 1431590Srgrimes 14493441Sdwmalonestatic void 14524665Salexhead_bytes(fp, cnt) 14685859Salfred FILE *fp; 14793441Sdwmalone size_t cnt; 14824665Salex{ 14924665Salex char buf[4096]; 15093441Sdwmalone size_t readlen; 15124665Salex 15224665Salex while (cnt) { 15324665Salex if (cnt < sizeof(buf)) 15424665Salex readlen = cnt; 15524665Salex else 15624665Salex readlen = sizeof(buf); 15724665Salex readlen = fread(buf, sizeof(char), readlen, fp); 15840114Sdes if (readlen == 0) 15924665Salex break; 16024665Salex if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 16127314Scharnier err(1, "stdout"); 16224665Salex cnt -= readlen; 16324665Salex } 16424665Salex} 16524665Salex 16693441Sdwmalonestatic void 1671590Srgrimesobsolete(argv) 1681590Srgrimes char *argv[]; 1691590Srgrimes{ 1701590Srgrimes char *ap; 1711590Srgrimes 17224665Salex while ((ap = *++argv)) { 1731590Srgrimes /* Return if "--" or not "-[0-9]*". */ 1741590Srgrimes if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 1751590Srgrimes return; 1761590Srgrimes if ((ap = malloc(strlen(*argv) + 2)) == NULL) 17727314Scharnier err(1, NULL); 1781590Srgrimes ap[0] = '-'; 1791590Srgrimes ap[1] = 'n'; 1801590Srgrimes (void)strcpy(ap + 2, *argv + 1); 1811590Srgrimes *argv = ap; 1821590Srgrimes } 1831590Srgrimes} 1841590Srgrimes 18593441Sdwmalonestatic void 1861590Srgrimesusage() 1871590Srgrimes{ 18885859Salfred 18989767Sdwmalone (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 1901590Srgrimes exit(1); 1911590Srgrimes} 192