Return to head.c CVS log

Up to [local] / src / usr.bin / head

Annotation of src/usr.bin/head/head.c, Revision 1.20

1.20    ! deraadt     1: /*     $OpenBSD: head.c,v 1.19 2015/10/07 06:55:10 deraadt 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: #include <stdio.h>
                     33: #include <stdlib.h>
                     34: #include <ctype.h>
1.4       aaron      35: #include <limits.h>
1.7       deraadt    36: #include <err.h>
1.4       aaron      37: #include <errno.h>
1.1       deraadt    38: #include <unistd.h>
                     39:
1.8       millert    40: static void usage(void);
1.1       deraadt    41:
                     42: /*
                     43:  * head - give the first few lines of a stream or of each of a set of files
                     44:  *
                     45:  * Bill Joy UCB August 24, 1977
                     46:  */
                     47:
                     48: int
1.11      deraadt    49: main(int argc, char *argv[])
1.1       deraadt    50: {
1.18      schwarze   51:        FILE    *fp;
1.9       mpech      52:        long    cnt;
1.4       aaron      53:        int     ch, firsttime;
                     54:        long    linecnt = 10;
1.12      ray        55:        char    *p = NULL;
1.17      tedu       56:        int     status = 0;
1.1       deraadt    57:
1.20    ! deraadt    58:        if (pledge("stdio rpath", NULL) == -1)
        !            59:                err(1, "pledge");
1.19      deraadt    60:
1.1       deraadt    61:        /* handle obsolete -number syntax */
1.16      deraadt    62:        if (argc > 1 && argv[1][0] == '-' &&
                     63:            isdigit((unsigned char)argv[1][1])) {
1.12      ray        64:                p = argv[1] + 1;
1.13      tedu       65:                argc--;
                     66:                argv++;
1.1       deraadt    67:        }
                     68:
1.13      tedu       69:        while ((ch = getopt(argc, argv, "n:")) != -1) {
1.1       deraadt    70:                switch (ch) {
                     71:                case 'n':
1.12      ray        72:                        p = optarg;
1.1       deraadt    73:                        break;
                     74:                default:
                     75:                        usage();
                     76:                }
1.13      tedu       77:        }
1.1       deraadt    78:        argc -= optind, argv += optind;
                     79:
1.4       aaron      80:        if (p) {
1.12      ray        81:                const char *errstr;
                     82:
                     83:                linecnt = strtonum(p, 1, LONG_MAX, &errstr);
                     84:                if (errstr)
                     85:                        errx(1, "line count %s: %s", errstr, p);
1.4       aaron      86:        }
                     87:
1.1       deraadt    88:        for (firsttime = 1; ; firsttime = 0) {
                     89:                if (!*argv) {
                     90:                        if (!firsttime)
1.17      tedu       91:                                exit(status);
1.18      schwarze   92:                        fp = stdin;
1.20    ! deraadt    93:                        if (pledge("stdio", NULL) == -1)
        !            94:                                err(1, "pledge");
1.13      tedu       95:                } else {
1.18      schwarze   96:                        if ((fp = fopen(*argv, "r")) == NULL) {
1.5       aaron      97:                                warn("%s", *argv++);
1.17      tedu       98:                                status = 1;
1.4       aaron      99:                                continue;
1.1       deraadt   100:                        }
                    101:                        if (argc > 1) {
                    102:                                if (!firsttime)
                    103:                                        putchar('\n');
                    104:                                printf("==> %s <==\n", *argv);
                    105:                        }
                    106:                        ++argv;
                    107:                }
1.18      schwarze  108:                for (cnt = linecnt; cnt && !feof(fp); --cnt)
                    109:                        while ((ch = getc(fp)) != EOF)
1.1       deraadt   110:                                if (putchar(ch) == '\n')
                    111:                                        break;
1.18      schwarze  112:                fclose(fp);
1.1       deraadt   113:        }
                    114:        /*NOTREACHED*/
                    115: }
                    116:
                    117:
                    118: static void
1.11      deraadt   119: usage(void)
1.1       deraadt   120: {
1.14      jmc       121:        fputs("usage: head [-count | -n count] [file ...]\n", stderr);
1.1       deraadt   122:        exit(1);
                    123: }