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Annotation of src/usr.bin/head/head.c, Revision 1.11

1.11    ! deraadt     1: /*     $OpenBSD: head.c,v 1.10 2003/06/03 02:56:09 millert Exp $       */
1.2       deraadt     2:
1.1       deraadt     3: /*
                      4:  * Copyright (c) 1980, 1987 Regents of the University of California.
                      5:  * 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.
1.10      millert    15:  * 3. Neither the name of the University nor the names of its contributors
1.1       deraadt    16:  *    may be used to endorse or promote products derived from this software
                     17:  *    without specific prior written permission.
                     18:  *
                     19:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     20:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     21:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     22:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     23:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     24:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     25:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     26:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     27:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     28:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     29:  * SUCH DAMAGE.
                     30:  */
                     31:
                     32: #ifndef lint
                     33: char copyright[] =
                     34: "@(#) Copyright (c) 1980, 1987 Regents of the University of California.\n\
                     35:  All rights reserved.\n";
                     36: #endif /* not lint */
                     37:
                     38: #ifndef lint
                     39: /*static char sccsid[] = "from: @(#)head.c     5.5 (Berkeley) 6/1/90";*/
1.11    ! deraadt    40: static char rcsid[] = "$OpenBSD: head.c,v 1.10 2003/06/03 02:56:09 millert Exp $";
1.1       deraadt    41: #endif /* not lint */
                     42:
                     43: #include <stdio.h>
                     44: #include <stdlib.h>
                     45: #include <ctype.h>
1.4       aaron      46: #include <limits.h>
1.7       deraadt    47: #include <err.h>
1.4       aaron      48: #include <errno.h>
1.1       deraadt    49: #include <unistd.h>
                     50:
1.8       millert    51: static void usage(void);
1.1       deraadt    52:
                     53: /*
                     54:  * head - give the first few lines of a stream or of each of a set of files
                     55:  *
                     56:  * Bill Joy UCB August 24, 1977
                     57:  */
                     58:
                     59: int
1.11    ! deraadt    60: main(int argc, char *argv[])
1.1       deraadt    61: {
1.9       mpech      62:        long    cnt;
1.4       aaron      63:        int     ch, firsttime;
                     64:        long    linecnt = 10;
                     65:        char    *inval = NULL, *p = NULL;
1.1       deraadt    66:
                     67:        /* handle obsolete -number syntax */
                     68:        if (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) {
1.4       aaron      69:                linecnt = strtol((p = argv[1] + 1), &inval, 10);
1.1       deraadt    70:                argc--; argv++;
                     71:        }
                     72:
1.3       millert    73:        while ((ch = getopt (argc, argv, "n:")) != -1)
1.1       deraadt    74:                switch (ch) {
                     75:                case 'n':
1.4       aaron      76:                        linecnt = strtol((p = optarg), &inval, 10);
1.1       deraadt    77:                        break;
                     78:                default:
                     79:                        usage();
                     80:                }
                     81:        argc -= optind, argv += optind;
                     82:
1.4       aaron      83:        if (p) {
                     84:                if ((linecnt == LONG_MIN || linecnt == LONG_MAX) &&
                     85:                    errno == ERANGE)
1.5       aaron      86:                        err(1, "illegal line count -- %s", p);
1.4       aaron      87:                else if (linecnt <= 0 || *inval)
1.5       aaron      88:                        errx(1, "illegal line count -- %s", p);
1.4       aaron      89:        }
                     90:
1.1       deraadt    91:        /* setlinebuf(stdout); */
                     92:        for (firsttime = 1; ; firsttime = 0) {
                     93:                if (!*argv) {
                     94:                        if (!firsttime)
                     95:                                exit(0);
                     96:                }
                     97:                else {
                     98:                        if (!freopen(*argv, "r", stdin)) {
1.5       aaron      99:                                warn("%s", *argv++);
1.4       aaron     100:                                continue;
1.1       deraadt   101:                        }
                    102:                        if (argc > 1) {
                    103:                                if (!firsttime)
                    104:                                        putchar('\n');
                    105:                                printf("==> %s <==\n", *argv);
                    106:                        }
                    107:                        ++argv;
                    108:                }
1.4       aaron     109:                for (cnt = linecnt; cnt && !feof(stdin); --cnt)
1.1       deraadt   110:                        while ((ch = getchar()) != EOF)
                    111:                                if (putchar(ch) == '\n')
                    112:                                        break;
                    113:        }
                    114:        /*NOTREACHED*/
                    115: }
                    116:
                    117:
                    118: static void
1.11    ! deraadt   119: usage(void)
1.1       deraadt   120: {
                    121:        fputs("usage: head [-n line_count] [file ...]\n", stderr);
                    122:        exit(1);
                    123: }
                    124: