1 /* date - print or set the system date and time
2 Copyright (C) 1989-2005 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 David MacKenzie <djm@gnu.ai.mit.edu> */
23 #include <sys/types.h>
24 #if HAVE_LANGINFO_CODESET
25 # include <langinfo.h>
39 /* The official name of this program (e.g., no `g' prefix). */
40 #define PROGRAM_NAME "date"
42 #define AUTHORS "David MacKenzie"
46 static bool show_date (const char *format, struct timespec when);
50 /* display only the date: 1999-03-25 */
52 /* display date and hour: 1999-03-25T03-0500 */
54 /* display date, hours, and minutes: 1999-03-25T03:23-0500 */
56 /* display date, hours, minutes, and seconds: 1999-03-25T03:23:14-0500 */
58 /* similar, but display nanoseconds: 1999-03-25T03:23:14,123456789-0500 */
62 static char const *const time_spec_string[] =
64 "date", "hours", "minutes", "seconds", "ns", 0
67 static enum Time_spec const time_spec[] =
69 TIME_SPEC_DATE, TIME_SPEC_HOURS, TIME_SPEC_MINUTES, TIME_SPEC_SECONDS,
73 /* The name this program was run with, for error messages. */
76 /* If nonzero, display an ISO 8601 format date/time string */
77 static int iso_8601_format = 0;
79 /* If true, display time in RFC-(2)822 format for mail or news. */
80 static bool rfc_format = false;
82 #define COMMON_SHORT_OPTIONS "Rd:f:r:s:u"
84 static struct option const long_options[] =
86 {"date", required_argument, NULL, 'd'},
87 {"file", required_argument, NULL, 'f'},
88 {"iso-8601", optional_argument, NULL, 'I'},
89 {"reference", required_argument, NULL, 'r'},
90 {"rfc-822", no_argument, NULL, 'R'},
91 {"rfc-2822", no_argument, NULL, 'R'},
92 {"set", required_argument, NULL, 's'},
93 {"uct", no_argument, NULL, 'u'},
94 {"utc", no_argument, NULL, 'u'},
95 {"universal", no_argument, NULL, 'u'},
96 {GETOPT_HELP_OPTION_DECL},
97 {GETOPT_VERSION_OPTION_DECL},
102 # define TZSET tzset ()
104 # define TZSET /* empty */
108 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
110 # define DATE_FMT_LANGINFO() ""
116 if (status != EXIT_SUCCESS)
117 fprintf (stderr, _("Try `%s --help' for more information.\n"),
122 Usage: %s [OPTION]... [+FORMAT]\n\
123 or: %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
125 program_name, program_name);
127 Display the current time in the given FORMAT, or set the system date.\n\
129 -d, --date=STRING display time described by STRING, not `now'\n\
130 -f, --file=DATEFILE like --date once for each line of DATEFILE\n\
131 --iso-8601[=TIMESPEC] output date/time in ISO 8601 format.\n\
132 TIMESPEC=`date' for date only (the default),\n\
133 `hours', `minutes', `seconds', or `ns' for date and\n\
134 time to the indicated precision.\n\
137 -r, --reference=FILE display the last modification time of FILE\n\
138 -R, --rfc-2822 output RFC-2822 compliant date string\n\
139 -s, --set=STRING set time described by STRING\n\
140 -u, --utc, --universal print or set Coordinated Universal Time\n\
142 fputs (HELP_OPTION_DESCRIPTION, stdout);
143 fputs (VERSION_OPTION_DESCRIPTION, stdout);
146 FORMAT controls the output. The only valid option for the second form\n\
147 specifies Coordinated Universal Time. Interpreted sequences are:\n\
150 %a locale's abbreviated weekday name (e.g., Sun)\n\
153 %A locale's full weekday name (e.g., Sunday)\n\
154 %b locale's abbreviated month name (e.g., Jan)\n\
155 %B locale's full month name (e.g., January)\n\
156 %c locale's date and time (e.g., Thu Mar 3 23:05:25 2005)\n\
159 %C century; like %Y, except omit last two digits (e.g., 21)\n\
160 %d day of month (e.g, 01)\n\
161 %D date; same as %m/%d/%y\n\
162 %e day of month, space padded; same as %_d\n\
165 %F full date; same as %Y-%m-%d\n\
166 %g the last two digits of the year corresponding to the %V week number\n\
167 %G the year corresponding to the %V week number\n\
173 %j day of year (001..366)\n\
179 %M minute (00..59)\n\
183 %N nanoseconds (000000000..999999999)\n\
184 %p locale's equivalent of either AM or PM; blank if not known\n\
185 %P like %p, but lower case\n\
186 %r locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
187 %R 24-hour hour and minute; same as %H:%M\n\
188 %s seconds since 1970-01-01 00:00:00 UTC\n\
191 %S second (00..60)\n\
193 %T time; same as %H:%M:%S\n\
194 %u day of week (1..7); 1 is Monday\n\
197 %U week number of year with Sunday as first day of week (00..53)\n\
198 %V week number of year with Monday as first day of week (01..53)\n\
199 %w day of week (0..6); 0 is Sunday\n\
200 %W week number of year with Monday as first day of week (00..53)\n\
203 %x locale's date representation (e.g., 12/31/99)\n\
204 %X locale's time representation (e.g., 23:13:48)\n\
205 %y last two digits of year (00..99)\n\
209 %z numeric timezone (e.g., -0400)\n\
210 %Z alphabetic time zone abbreviation (e.g., EDT)\n\
212 By default, date pads numeric fields with zeroes.\n\
213 The following optional flags may follow `%':\n\
215 - (hyphen) do not pad the field\n\
216 _ (underscore) pad with spaces\n\
217 0 (zero) pad with zeros\n\
218 ^ use upper case if possible\n\
219 # use opposite case if possible\n\
223 After any flags comes an optional field width, as a decimal number;\n\
224 then an optional modifier, which is either\n\
225 E to use the locale's alternate representations if available, or\n\
226 O to use the locale's alternate numeric symbols if available.\n\
228 printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
233 /* Parse each line in INPUT_FILENAME as with --date and display each
234 resulting time and date. If the file cannot be opened, tell why
235 then exit. Issue a diagnostic for any lines that cannot be parsed.
236 Return true if successful. */
239 batch_convert (const char *input_filename, const char *format)
245 struct timespec when;
247 if (STREQ (input_filename, "-"))
249 input_filename = _("standard input");
254 in_stream = fopen (input_filename, "r");
255 if (in_stream == NULL)
257 error (EXIT_FAILURE, errno, "%s", quote (input_filename));
266 ssize_t line_length = getline (&line, &buflen, in_stream);
269 /* FIXME: detect/handle error here. */
273 if (! get_date (&when, line, NULL))
275 if (line[line_length - 1] == '\n')
276 line[line_length - 1] = '\0';
277 error (0, 0, _("invalid date `%s'"), line);
282 ok &= show_date (format, when);
286 if (fclose (in_stream) == EOF)
287 error (EXIT_FAILURE, errno, "%s", quote (input_filename));
296 main (int argc, char **argv)
299 const char *datestr = NULL;
300 const char *set_datestr = NULL;
301 struct timespec when;
302 bool set_date = false;
304 char *batch_file = NULL;
305 char *reference = NULL;
306 struct stat refstats;
309 int option_specified_date;
310 char const *short_options = (posix2_version () < 200112
311 ? COMMON_SHORT_OPTIONS "I::"
312 : COMMON_SHORT_OPTIONS "I:");
314 initialize_main (&argc, &argv);
315 program_name = argv[0];
316 setlocale (LC_ALL, "");
317 bindtextdomain (PACKAGE, LOCALEDIR);
318 textdomain (PACKAGE);
320 atexit (close_stdout);
322 while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
333 iso_8601_format = (optarg
334 ? XARGMATCH ("--iso-8601", optarg,
335 time_spec_string, time_spec)
345 set_datestr = optarg;
349 /* POSIX says that `date -u' is equivalent to setting the TZ
350 environment variable, so this option should do nothing other
352 if (putenv ("TZ=UTC0") != 0)
356 case_GETOPT_HELP_CHAR;
357 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
359 usage (EXIT_FAILURE);
362 n_args = argc - optind;
364 option_specified_date = ((datestr ? 1 : 0)
365 + (batch_file ? 1 : 0)
366 + (reference ? 1 : 0));
368 if (option_specified_date > 1)
371 _("the options to specify dates for printing are mutually exclusive"));
372 usage (EXIT_FAILURE);
375 if (set_date && option_specified_date)
378 _("the options to print and set the time may not be used together"));
379 usage (EXIT_FAILURE);
384 error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
385 usage (EXIT_FAILURE);
388 if ((set_date || option_specified_date)
389 && n_args == 1 && argv[optind][0] != '+')
392 the argument `%s' lacks a leading `+';\n\
393 When using an option to specify date(s), any non-option\n\
394 argument must be a format string beginning with `+'."),
396 usage (EXIT_FAILURE);
399 /* Simply ignore --rfc-2822 if specified when setting the date. */
400 if (rfc_format && !set_date && n_args > 0)
403 _("a format string may not be specified when using\
404 the --rfc-2822 (-R) option"));
405 usage (EXIT_FAILURE);
409 datestr = set_datestr;
411 if (batch_file != NULL)
412 ok = batch_convert (batch_file, (n_args == 1 ? argv[optind] + 1 : NULL));
415 bool valid_date = true;
418 if (!option_specified_date && !set_date)
420 if (n_args == 1 && argv[optind][0] != '+')
422 /* Prepare to set system clock to the specified date/time
423 given in the POSIX-format. */
425 datestr = argv[optind];
426 valid_date = posixtime (&when.tv_sec,
429 | PDS_CENTURY | PDS_SECONDS));
430 when.tv_nsec = 0; /* FIXME: posixtime should set this. */
435 /* Prepare to print the current date/time. */
436 datestr = _("undefined");
438 format = (n_args == 1 ? argv[optind] + 1 : NULL);
443 /* (option_specified_date || set_date) */
444 if (reference != NULL)
446 if (stat (reference, &refstats))
447 error (EXIT_FAILURE, errno, "%s", reference);
448 when.tv_sec = refstats.st_mtime;
449 when.tv_nsec = TIMESPEC_NS (refstats.st_mtim);
453 valid_date = get_date (&when, datestr, NULL);
456 format = (n_args == 1 ? argv[optind] + 1 : NULL);
460 error (EXIT_FAILURE, 0, _("invalid date `%s'"), datestr);
464 /* Set the system clock to the specified date, then regardless of
465 the success of that operation, format and print that date. */
466 if (settime (&when) != 0)
468 error (0, errno, _("cannot set date"));
473 ok &= show_date (format, when);
476 exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
479 /* Display the date and/or time in WHEN according to the format specified
480 in FORMAT, followed by a newline. If FORMAT is NULL, use the
481 standard output format (ctime style but with a timezone inserted).
482 Return true if successful. */
485 show_date (const char *format, struct timespec when)
489 size_t out_length = 0;
490 /* ISO 8601 formats. See below regarding %z */
491 static char const * const iso_format_string[] =
496 "%Y-%m-%dT%H:%M:%S%z",
497 "%Y-%m-%dT%H:%M:%S,%N%z"
503 format = "%a, %d %b %Y %H:%M:%S %z";
504 else if (iso_8601_format)
505 format = iso_format_string[iso_8601_format - 1];
508 char *date_fmt = DATE_FMT_LANGINFO ();
509 /* Do not wrap the following literal format string with _(...).
510 For example, suppose LC_ALL is unset, LC_TIME="POSIX",
511 and LANG="ko_KR". In that case, POSIX says that LC_TIME
512 determines the format and contents of date and time strings
513 written by date, which means "date" must generate output
514 using the POSIX locale; but adding _() would cause "date"
515 to use a Korean translation of the format. */
516 format = *date_fmt ? date_fmt : "%a %b %e %H:%M:%S %Z %Y";
519 else if (*format == '\0')
525 tm = localtime (&when.tv_sec);
528 char buf[INT_BUFSIZE_BOUND (intmax_t)];
529 error (0, 0, _("time %s is out of range"),
530 (TYPE_SIGNED (time_t)
531 ? imaxtostr (when.tv_sec, buf)
532 : umaxtostr (when.tv_sec, buf)));
540 out = x2nrealloc (out, &out_length, sizeof *out);
542 /* Mark the first byte of the buffer so we can detect the case
543 of nstrftime producing an empty string. Otherwise, this loop
544 would not terminate when date was invoked like this
545 `LANG=de date +%p' on a system with good language support. */
549 setlocale (LC_ALL, "C");
551 done = (nstrftime (out, out_length, format, tm, 0, when.tv_nsec)
555 setlocale (LC_ALL, "");
561 printf ("%s\n", out);