1 /* head - copy first part of files. */
3 /* See Makefile for compilation details. */
6 Copyright (C) 1999-2009 Free Software Foundation, Inc.
8 This file is part of GNU Bash.
9 Bash is free software: you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation, either version 3 of the License, or
12 (at your option) any later version.
14 Bash is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with Bash. If not, see <http://www.gnu.org/licenses/>.
25 #include "bashtypes.h"
26 #include "posixstat.h"
29 #if defined (HAVE_UNISTD_H)
37 #include "chartypes.h"
41 #include "bashgetopt.h"
56 for (l = list; l; l = l->next)
59 if (arg[0] != '-' || arg[1] == '-' || (DIGIT(arg[1]) == 0))
62 wd = make_bare_word (arg+1);
63 nl = make_word_list (wd, l->next);
64 l->word->word[1] = 'n';
65 l->word->word[2] = '\0';
67 l = nl; /* skip over new argument */
80 while ((ch = getc (fp)) != EOF)
82 if (putchar (ch) == EOF)
84 builtin_error ("write error: %s", strerror (errno));
85 return EXECUTION_FAILURE;
102 munge_list (list); /* change -num into -n num */
104 reset_internal_getopt ();
106 while ((opt = internal_getopt (list, "n:")) != -1)
111 nline = atoi (list_optarg);
114 builtin_error ("bad line count: %s", list_optarg);
126 return (file_head (stdin, nline));
128 for (rval = EXECUTION_SUCCESS, opt = 1, l = list; l; l = l->next)
130 fp = fopen (l->word->word, "r");
133 builtin_error ("%s: %s", l->word->word, strerror (errno));
136 if (list->next) /* more than one file */
138 printf ("%s==> %s <==\n", opt ? "" : "\n", l->word->word);
141 rval = file_head (fp, nline);
149 "Display lines from beginning of file.",
151 "Copy the first N lines from the input files to the standard output.",
152 "N is supplied as an argument to the `-n' option. If N is not given,",
153 "the first ten lines are copied.",
157 struct builtin head_struct = {
158 "head", /* builtin name */
159 head_builtin, /* function implementing the builtin */
160 BUILTIN_ENABLED, /* initial flags for builtin */
161 head_doc, /* array of long documentation strings. */
162 "head [-n num] [file ...]", /* usage synopsis; becomes short_doc */
163 0 /* reserved for internal use */