161f28255Scgd /* 261f28255Scgd * Copyright (c) 1980, 1987 Regents of the University of California. 361f28255Scgd * All rights reserved. 461f28255Scgd * 561f28255Scgd * Redistribution and use in source and binary forms, with or without 661f28255Scgd * modification, are permitted provided that the following conditions 761f28255Scgd * are met: 861f28255Scgd * 1. Redistributions of source code must retain the above copyright 961f28255Scgd * notice, this list of conditions and the following disclaimer. 1061f28255Scgd * 2. Redistributions in binary form must reproduce the above copyright 1161f28255Scgd * notice, this list of conditions and the following disclaimer in the 1261f28255Scgd * documentation and/or other materials provided with the distribution. 1361f28255Scgd * 3. All advertising materials mentioning features or use of this software 1461f28255Scgd * must display the following acknowledgement: 1561f28255Scgd * This product includes software developed by the University of 1661f28255Scgd * California, Berkeley and its contributors. 1761f28255Scgd * 4. Neither the name of the University nor the names of its contributors 1861f28255Scgd * may be used to endorse or promote products derived from this software 1961f28255Scgd * without specific prior written permission. 2061f28255Scgd * 2161f28255Scgd * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2261f28255Scgd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2361f28255Scgd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2461f28255Scgd * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2561f28255Scgd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2661f28255Scgd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2761f28255Scgd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2861f28255Scgd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2961f28255Scgd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3061f28255Scgd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3161f28255Scgd * SUCH DAMAGE. 3261f28255Scgd */ 3361f28255Scgd 3461f28255Scgd #ifndef lint 3561f28255Scgd char copyright[] = 3661f28255Scgd "@(#) Copyright (c) 1980, 1987 Regents of the University of California.\n\ 3761f28255Scgd All rights reserved.\n"; 3861f28255Scgd #endif /* not lint */ 3961f28255Scgd 4061f28255Scgd #ifndef lint 4161f28255Scgd static char sccsid[] = "@(#)head.c 5.5 (Berkeley) 6/1/90"; 4261f28255Scgd #endif /* not lint */ 4361f28255Scgd 4461f28255Scgd #include <stdio.h> 45*aab7593aSjtc #include <stdlib.h> 4661f28255Scgd #include <ctype.h> 47*aab7593aSjtc 48*aab7593aSjtc static void usage (); 49*aab7593aSjtc 5061f28255Scgd /* 5161f28255Scgd * head - give the first few lines of a stream or of each of a set of files 5261f28255Scgd * 5361f28255Scgd * Bill Joy UCB August 24, 1977 5461f28255Scgd */ 5561f28255Scgd 5661f28255Scgd main(argc, argv) 5761f28255Scgd int argc; 5861f28255Scgd char **argv; 5961f28255Scgd { 6061f28255Scgd register int ch, cnt; 6161f28255Scgd int firsttime, linecnt = 10; 6261f28255Scgd 63*aab7593aSjtc /* handle obsolete -number syntax */ 64*aab7593aSjtc if (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) { 6561f28255Scgd if ((linecnt = atoi(argv[1] + 1)) < 0) { 66*aab7593aSjtc usage (); 6761f28255Scgd } 68*aab7593aSjtc argc--; argv++; 6961f28255Scgd } 70*aab7593aSjtc 71*aab7593aSjtc while ((ch = getopt (argc, argv, "n:")) != EOF) 72*aab7593aSjtc switch (ch) { 73*aab7593aSjtc case 'n': 74*aab7593aSjtc if ((linecnt = atoi(optarg)) < 0) 75*aab7593aSjtc usage (); 76*aab7593aSjtc break; 77*aab7593aSjtc 78*aab7593aSjtc default: 79*aab7593aSjtc usage(); 80*aab7593aSjtc } 81*aab7593aSjtc argc -= optind, argv += optind; 82*aab7593aSjtc 8361f28255Scgd /* setlinebuf(stdout); */ 84*aab7593aSjtc for (firsttime = 1; ; firsttime = 0) { 8561f28255Scgd if (!*argv) { 8661f28255Scgd if (!firsttime) 8761f28255Scgd exit(0); 8861f28255Scgd } 8961f28255Scgd else { 9061f28255Scgd if (!freopen(*argv, "r", stdin)) { 9161f28255Scgd fprintf(stderr, "head: can't read %s.\n", *argv); 9261f28255Scgd exit(1); 9361f28255Scgd } 9461f28255Scgd if (argc > 1) { 9561f28255Scgd if (!firsttime) 9661f28255Scgd putchar('\n'); 9761f28255Scgd printf("==> %s <==\n", *argv); 9861f28255Scgd } 9961f28255Scgd ++argv; 10061f28255Scgd } 10161f28255Scgd for (cnt = linecnt; cnt; --cnt) 10261f28255Scgd while ((ch = getchar()) != EOF) 10361f28255Scgd if (putchar(ch) == '\n') 10461f28255Scgd break; 10561f28255Scgd } 10661f28255Scgd /*NOTREACHED*/ 10761f28255Scgd } 108*aab7593aSjtc 109*aab7593aSjtc 110*aab7593aSjtc static void 111*aab7593aSjtc usage () 112*aab7593aSjtc { 113*aab7593aSjtc fputs("usage: head [-n line_count] [file ...]\n", stderr); 114*aab7593aSjtc exit(1); 115*aab7593aSjtc } 116*aab7593aSjtc 117