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