| 1 | /* head - copy first part of files. */
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| 2 |
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| 3 | /* See Makefile for compilation details. */
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| 4 |
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| 5 | #include "config.h"
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| 6 |
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| 7 | #include "bashtypes.h"
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| 8 | #include "posixstat.h"
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| 9 | #include "filecntl.h"
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| 10 |
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| 11 | #if defined (HAVE_UNISTD_H)
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| 12 | # include <unistd.h>
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| 13 | #endif
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| 14 |
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| 15 | #include "bashansi.h"
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| 16 |
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| 17 | #include <stdio.h>
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| 18 | #include <errno.h>
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| 19 | #include "chartypes.h"
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| 20 |
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| 21 | #include "builtins.h"
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| 22 | #include "shell.h"
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| 23 | #include "bashgetopt.h"
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| 24 |
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| 25 | #if !defined (errno)
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| 26 | extern int errno;
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| 27 | #endif
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| 28 |
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| 29 | static void
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| 30 | munge_list (list)
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| 31 | WORD_LIST *list;
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| 32 | {
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| 33 | WORD_LIST *l, *nl;
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| 34 | WORD_DESC *wd;
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| 35 | char *arg;
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| 36 |
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| 37 | for (l = list; l; l = l->next)
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| 38 | {
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| 39 | arg = l->word->word;
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| 40 | if (arg[0] != '-' || arg[1] == '-' || (DIGIT(arg[1]) == 0))
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| 41 | return;
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| 42 | /* We have -[0-9]* */
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| 43 | wd = make_bare_word (arg+1);
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| 44 | nl = make_word_list (wd, l->next);
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| 45 | l->word->word[1] = 'n';
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| 46 | l->word->word[2] = '\0';
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| 47 | l->next = nl;
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| 48 | l = nl; /* skip over new argument */
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| 49 | }
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| 50 | }
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| 51 |
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| 52 | static int
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| 53 | file_head (fp, cnt)
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| 54 | FILE *fp;
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| 55 | int cnt;
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| 56 | {
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| 57 | int ch;
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| 58 |
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| 59 | while (cnt--)
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| 60 | {
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| 61 | while ((ch = getc (fp)) != EOF)
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| 62 | {
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| 63 | if (putchar (ch) == EOF)
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| 64 | {
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| 65 | builtin_error ("write error: %s", strerror (errno));
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| 66 | return EXECUTION_FAILURE;
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| 67 | }
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| 68 | if (ch == '\n')
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| 69 | break;
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| 70 | }
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| 71 | }
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| 72 | }
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| 73 |
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| 74 | head_builtin (list)
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| 75 | WORD_LIST *list;
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| 76 | {
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| 77 | int nline, opt, rval;
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| 78 | WORD_LIST *l;
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| 79 | FILE *fp;
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| 80 |
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| 81 | char *t;
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| 82 |
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| 83 | munge_list (list); /* change -num into -n num */
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| 84 |
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| 85 | reset_internal_getopt ();
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| 86 | nline = 10;
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| 87 | while ((opt = internal_getopt (list, "n:")) != -1)
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| 88 | {
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| 89 | switch (opt)
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| 90 | {
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| 91 | case 'n':
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| 92 | nline = atoi (list_optarg);
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| 93 | if (nline <= 0)
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| 94 | {
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| 95 | builtin_error ("bad line count: %s", list_optarg);
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| 96 | return (EX_USAGE);
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| 97 | }
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| 98 | break;
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| 99 | default:
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| 100 | builtin_usage ();
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| 101 | return (EX_USAGE);
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| 102 | }
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| 103 | }
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| 104 | list = loptend;
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| 105 |
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| 106 | if (list == 0)
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| 107 | return (file_head (stdin, nline));
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| 108 |
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| 109 | for (rval = EXECUTION_SUCCESS, opt = 1, l = list; l; l = l->next)
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| 110 | {
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| 111 | fp = fopen (l->word->word, "r");
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| 112 | if (fp == NULL)
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| 113 | {
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| 114 | builtin_error ("%s: %s", l->word->word, strerror (errno));
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| 115 | continue;
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| 116 | }
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| 117 | if (list->next) /* more than one file */
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| 118 | {
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| 119 | printf ("%s==> %s <==\n", opt ? "" : "\n", l->word->word);
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| 120 | opt = 0;
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| 121 | }
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| 122 | rval = file_head (fp, nline);
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| 123 | fclose (fp);
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| 124 | }
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| 125 |
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| 126 | return (rval);
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| 127 | }
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| 128 |
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| 129 | char *head_doc[] = {
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| 130 | "Copy the first N lines from the input files to the standard output.",
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| 131 | "N is supplied as an argument to the `-n' option. If N is not given,",
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| 132 | "the first ten lines are copied.",
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| 133 | (char *)NULL
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| 134 | };
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| 135 |
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| 136 | struct builtin head_struct = {
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| 137 | "head", /* builtin name */
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| 138 | head_builtin, /* function implementing the builtin */
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| 139 | BUILTIN_ENABLED, /* initial flags for builtin */
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| 140 | head_doc, /* array of long documentation strings. */
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| 141 | "head [-n num] [file ...]", /* usage synopsis; becomes short_doc */
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| 142 | 0 /* reserved for internal use */
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| 143 | };
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