head.c revision 99112
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 */ 4599112Sobrien#include <sys/cdefs.h> 4699112Sobrien__FBSDID("$FreeBSD: head/usr.bin/head/head.c 99112 2002-06-30 05:25:07Z obrien $"); 471590Srgrimes 4895652Smarkm#include <sys/cdefs.h> 4995652Smarkm__FBSDID("$FreeBSD: head/usr.bin/head/head.c 99112 2002-06-30 05:25:07Z obrien $"); 5095652Smarkm 511590Srgrimes#include <sys/types.h> 5223693Speter 5323693Speter#include <ctype.h> 5427314Scharnier#include <err.h> 5523693Speter#include <stdio.h> 561590Srgrimes#include <stdlib.h> 571590Srgrimes#include <string.h> 5823693Speter#include <unistd.h> 591590Srgrimes 601590Srgrimes/* 611590Srgrimes * head - give the first few lines of a stream or of each of a set of files 621590Srgrimes * 631590Srgrimes * Bill Joy UCB August 24, 1977 641590Srgrimes */ 651590Srgrimes 6693441Sdwmalonestatic void head(FILE *, int); 6793441Sdwmalonestatic void head_bytes(FILE *, size_t); 6893441Sdwmalonestatic void obsolete(char *[]); 6993441Sdwmalonestatic void usage(void); 701590Srgrimes 711590Srgrimesint 7295652Smarkmmain(int argc, char *argv[]) 731590Srgrimes{ 7493441Sdwmalone int ch; 751590Srgrimes FILE *fp; 7685859Salfred int first, linecnt = -1, bytecnt = -1, eval = 0; 771590Srgrimes char *ep; 781590Srgrimes 791590Srgrimes obsolete(argv); 8024665Salex while ((ch = getopt(argc, argv, "n:c:")) != -1) 811590Srgrimes switch(ch) { 8224665Salex case 'c': 8324665Salex bytecnt = strtol(optarg, &ep, 10); 8424665Salex if (*ep || bytecnt <= 0) 8527314Scharnier errx(1, "illegal byte count -- %s", optarg); 8624665Salex break; 871590Srgrimes case 'n': 881590Srgrimes linecnt = strtol(optarg, &ep, 10); 891590Srgrimes if (*ep || linecnt <= 0) 9027314Scharnier errx(1, "illegal line count -- %s", optarg); 911590Srgrimes break; 921590Srgrimes case '?': 931590Srgrimes default: 941590Srgrimes usage(); 951590Srgrimes } 961590Srgrimes argc -= optind; 971590Srgrimes argv += optind; 981590Srgrimes 9924665Salex if (linecnt != -1 && bytecnt != -1) 10027314Scharnier errx(1, "can't combine line and byte counts"); 10124665Salex if (linecnt == -1 ) 10224665Salex linecnt = 10; 10324665Salex if (*argv) { 1041590Srgrimes for (first = 1; *argv; ++argv) { 1051590Srgrimes if ((fp = fopen(*argv, "r")) == NULL) { 10627314Scharnier warn("%s", *argv); 10727328Scharnier eval = 1; 1081590Srgrimes continue; 1091590Srgrimes } 1101590Srgrimes if (argc > 1) { 1111590Srgrimes (void)printf("%s==> %s <==\n", 1121590Srgrimes first ? "" : "\n", *argv); 1131590Srgrimes first = 0; 1141590Srgrimes } 11524665Salex if (bytecnt == -1) 11624665Salex head(fp, linecnt); 11724665Salex else 11824665Salex head_bytes(fp, bytecnt); 1191590Srgrimes (void)fclose(fp); 1201590Srgrimes } 12185859Salfred } else if (bytecnt == -1) 12224665Salex head(stdin, linecnt); 1231590Srgrimes else 12424665Salex head_bytes(stdin, bytecnt); 12524665Salex 1261590Srgrimes exit(eval); 1271590Srgrimes} 1281590Srgrimes 12993441Sdwmalonestatic void 13095652Smarkmhead(FILE *fp, int cnt) 1311590Srgrimes{ 13285861Salfred char *cp; 13393441Sdwmalone size_t error, readlen; 1341590Srgrimes 13585861Salfred while (cnt && (cp = fgetln(fp, &readlen)) != NULL) { 13685861Salfred error = fwrite(cp, sizeof(char), readlen, stdout); 13785861Salfred if (error != readlen) 13885861Salfred err(1, "stdout"); 13985861Salfred cnt--; 14085861Salfred } 1411590Srgrimes} 1421590Srgrimes 14393441Sdwmalonestatic void 14495652Smarkmhead_bytes(FILE *fp, size_t cnt) 14524665Salex{ 14624665Salex char buf[4096]; 14793441Sdwmalone size_t readlen; 14824665Salex 14924665Salex while (cnt) { 15024665Salex if (cnt < sizeof(buf)) 15124665Salex readlen = cnt; 15224665Salex else 15324665Salex readlen = sizeof(buf); 15424665Salex readlen = fread(buf, sizeof(char), readlen, fp); 15540114Sdes if (readlen == 0) 15624665Salex break; 15724665Salex if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 15827314Scharnier err(1, "stdout"); 15924665Salex cnt -= readlen; 16024665Salex } 16124665Salex} 16224665Salex 16393441Sdwmalonestatic void 16495652Smarkmobsolete(char *argv[]) 1651590Srgrimes{ 1661590Srgrimes char *ap; 1671590Srgrimes 16824665Salex while ((ap = *++argv)) { 1691590Srgrimes /* Return if "--" or not "-[0-9]*". */ 1701590Srgrimes if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 1711590Srgrimes return; 1721590Srgrimes if ((ap = malloc(strlen(*argv) + 2)) == NULL) 17327314Scharnier err(1, NULL); 1741590Srgrimes ap[0] = '-'; 1751590Srgrimes ap[1] = 'n'; 1761590Srgrimes (void)strcpy(ap + 2, *argv + 1); 1771590Srgrimes *argv = ap; 1781590Srgrimes } 1791590Srgrimes} 1801590Srgrimes 18193441Sdwmalonestatic void 18295652Smarkmusage(void) 1831590Srgrimes{ 18485859Salfred 18589767Sdwmalone (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 1861590Srgrimes exit(1); 1871590Srgrimes} 188