1 /* vi: set sw=4 ts=4: */
3 * head implementation for busybox
5 * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
10 /* BB_AUDIT SUSv3 compliant */
11 /* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
12 /* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */
16 static const char head_opts[] ALIGN1 =
18 #if ENABLE_FEATURE_FANCY_HEAD
23 #if ENABLE_FEATURE_FANCY_HEAD
24 static const struct suffix_mult head_suffixes[] = {
32 static const char header_fmt_str[] ALIGN1 = "\n==> %s <==\n";
34 int head_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
35 int head_main(int argc, char **argv)
37 unsigned long count = 10;
39 #if ENABLE_FEATURE_FANCY_HEAD
41 int header_threshhold = 1;
49 int retval = EXIT_SUCCESS;
51 #if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD
52 /* Allow legacy syntax of an initial numeric option without -n. */
53 if (argc > 1 && argv[1][0] == '-'
54 && isdigit(argv[1][1])
63 /* No size benefit in converting this to getopt32 */
64 while ((opt = getopt(argc, argv, head_opts)) > 0) {
66 #if ENABLE_FEATURE_FANCY_HEAD
68 header_threshhold = INT_MAX;
71 header_threshhold = -1;
79 #if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD
83 #if !ENABLE_FEATURE_FANCY_HEAD
86 count = xatoul_sfx(p, head_suffixes);
99 fmt = header_fmt_str + 1;
100 #if ENABLE_FEATURE_FANCY_HEAD
101 if (argc - optind <= header_threshhold) {
102 header_threshhold = 0;
105 if (argc <= optind + 1) {
108 /* Now define some things here to avoid #ifdefs in the code below.
109 * These should optimize out of the if conditions below. */
110 #define header_threshhold 1
111 #define count_bytes 0
115 fp = fopen_or_warn_stdin(*argv);
118 *argv = (char *) bb_msg_standard_input;
120 if (header_threshhold) {
124 while (i && ((c = getc(fp)) != EOF)) {
125 if (count_bytes || (c == '\n')) {
130 if (fclose_if_not_stdin(fp)) {
131 bb_simple_perror_msg(*argv); /* Avoid multibyte problems. */
132 retval = EXIT_FAILURE;
134 die_if_ferror_stdout();
136 fmt = header_fmt_str;
139 fflush_stdout_and_exit(retval);