1 /* date - print or set the system date and time
2 Copyright (C) 1989-2004 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 (Sun..Sat)\n\
153 %A locale's full weekday name, variable length (Sunday..Saturday)\n\
154 %b locale's abbreviated month name (Jan..Dec)\n\
155 %B locale's full month name, variable length (January..December)\n\
156 %c locale's date and time (Sat Nov 04 12:02:33 EST 1989)\n\
159 %C century (year divided by 100 and truncated to an integer) [00-99]\n\
160 %d day of month (01..31)\n\
161 %D date (mm/dd/yy)\n\
162 %e day of month, blank padded ( 1..31)\n\
165 %F same as %Y-%m-%d\n\
166 %g the 2-digit year corresponding to the %V week number\n\
167 %G the 4-digit 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 upper case AM or PM indicator (blank in many locales)\n\
185 %P locale's lower case am or pm indicator (blank in many locales)\n\
186 %r time, 12-hour (hh:mm:ss [AP]M)\n\
187 %R time, 24-hour (hh:mm)\n\
188 %s seconds since `00:00:00 1970-01-01 UTC' (a GNU extension)\n\
191 %S second (00..60); the 60 is necessary to accommodate a leap second\n\
192 %t a horizontal tab\n\
193 %T time, 24-hour (hh:mm:ss)\n\
194 %u day of week (1..7); 1 represents 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 represents Sunday\n\
200 %W week number of year with Monday as first day of week (00..53)\n\
203 %x locale's date representation (mm/dd/yy)\n\
204 %X locale's time representation (%H:%M:%S)\n\
205 %y last two digits of year (00..99)\n\
209 %z RFC-2822 style numeric timezone (-0500) (a nonstandard extension)\n\
210 %Z time zone (e.g., EDT), or nothing if no time zone is determinable\n\
212 By default, date pads numeric fields with zeroes. GNU date recognizes\n\
213 the following modifiers between `%' and a numeric directive.\n\
215 `-' (hyphen) do not pad the field\n\
216 `_' (underscore) pad the field with spaces\n\
218 printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
223 /* Parse each line in INPUT_FILENAME as with --date and display each
224 resulting time and date. If the file cannot be opened, tell why
225 then exit. Issue a diagnostic for any lines that cannot be parsed.
226 Return true if successful. */
229 batch_convert (const char *input_filename, const char *format)
235 struct timespec when;
237 if (STREQ (input_filename, "-"))
239 input_filename = _("standard input");
244 in_stream = fopen (input_filename, "r");
245 if (in_stream == NULL)
247 error (EXIT_FAILURE, errno, "%s", quote (input_filename));
256 ssize_t line_length = getline (&line, &buflen, in_stream);
259 /* FIXME: detect/handle error here. */
263 if (! get_date (&when, line, NULL))
265 if (line[line_length - 1] == '\n')
266 line[line_length - 1] = '\0';
267 error (0, 0, _("invalid date `%s'"), line);
272 ok &= show_date (format, when);
276 if (fclose (in_stream) == EOF)
277 error (EXIT_FAILURE, errno, "%s", quote (input_filename));
286 main (int argc, char **argv)
289 const char *datestr = NULL;
290 const char *set_datestr = NULL;
291 struct timespec when;
292 bool set_date = false;
294 char *batch_file = NULL;
295 char *reference = NULL;
296 struct stat refstats;
299 int option_specified_date;
300 char const *short_options = (posix2_version () < 200112
301 ? COMMON_SHORT_OPTIONS "I::"
302 : COMMON_SHORT_OPTIONS "I:");
304 initialize_main (&argc, &argv);
305 program_name = argv[0];
306 setlocale (LC_ALL, "");
307 bindtextdomain (PACKAGE, LOCALEDIR);
308 textdomain (PACKAGE);
310 atexit (close_stdout);
312 while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
325 iso_8601_format = (optarg
326 ? XARGMATCH ("--iso-8601", optarg,
327 time_spec_string, time_spec)
337 set_datestr = optarg;
341 /* POSIX says that `date -u' is equivalent to setting the TZ
342 environment variable, so this option should do nothing other
344 if (putenv ("TZ=UTC0") != 0)
348 case_GETOPT_HELP_CHAR;
349 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
351 usage (EXIT_FAILURE);
354 n_args = argc - optind;
356 option_specified_date = ((datestr ? 1 : 0)
357 + (batch_file ? 1 : 0)
358 + (reference ? 1 : 0));
360 if (option_specified_date > 1)
363 _("the options to specify dates for printing are mutually exclusive"));
364 usage (EXIT_FAILURE);
367 if (set_date && option_specified_date)
370 _("the options to print and set the time may not be used together"));
371 usage (EXIT_FAILURE);
376 error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
377 usage (EXIT_FAILURE);
380 if ((set_date || option_specified_date)
381 && n_args == 1 && argv[optind][0] != '+')
384 the argument `%s' lacks a leading `+';\n\
385 When using an option to specify date(s), any non-option\n\
386 argument must be a format string beginning with `+'."),
388 usage (EXIT_FAILURE);
391 /* Simply ignore --rfc-2822 if specified when setting the date. */
392 if (rfc_format && !set_date && n_args > 0)
395 _("a format string may not be specified when using\
396 the --rfc-2822 (-R) option"));
397 usage (EXIT_FAILURE);
401 datestr = set_datestr;
403 if (batch_file != NULL)
404 ok = batch_convert (batch_file, (n_args == 1 ? argv[optind] + 1 : NULL));
407 bool valid_date = true;
410 if (!option_specified_date && !set_date)
412 if (n_args == 1 && argv[optind][0] != '+')
414 /* Prepare to set system clock to the specified date/time
415 given in the POSIX-format. */
417 datestr = argv[optind];
418 valid_date = posixtime (&when.tv_sec,
421 | PDS_CENTURY | PDS_SECONDS));
422 when.tv_nsec = 0; /* FIXME: posixtime should set this. */
427 /* Prepare to print the current date/time. */
428 datestr = _("undefined");
429 if (gettime (&when) != 0)
430 error (EXIT_FAILURE, errno, _("cannot get time of day"));
431 format = (n_args == 1 ? argv[optind] + 1 : NULL);
436 /* (option_specified_date || set_date) */
437 if (reference != NULL)
439 if (stat (reference, &refstats))
440 error (EXIT_FAILURE, errno, "%s", reference);
441 when.tv_sec = refstats.st_mtime;
442 when.tv_nsec = TIMESPEC_NS (refstats.st_mtim);
446 valid_date = get_date (&when, datestr, NULL);
449 format = (n_args == 1 ? argv[optind] + 1 : NULL);
453 error (EXIT_FAILURE, 0, _("invalid date `%s'"), datestr);
457 /* Set the system clock to the specified date, then regardless of
458 the success of that operation, format and print that date. */
459 if (settime (&when) != 0)
461 error (0, errno, _("cannot set date"));
466 ok &= show_date (format, when);
469 exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
472 /* Display the date and/or time in WHEN according to the format specified
473 in FORMAT, followed by a newline. If FORMAT is NULL, use the
474 standard output format (ctime style but with a timezone inserted).
475 Return true if successful. */
478 show_date (const char *format, struct timespec when)
482 size_t out_length = 0;
483 /* ISO 8601 formats. See below regarding %z */
484 static char const * const iso_format_string[] =
489 "%Y-%m-%dT%H:%M:%S%z",
490 "%Y-%m-%dT%H:%M:%S,%N%z"
496 format = "%a, %d %b %Y %H:%M:%S %z";
497 else if (iso_8601_format)
498 format = iso_format_string[iso_8601_format - 1];
501 char *date_fmt = DATE_FMT_LANGINFO ();
502 /* Do not wrap the following literal format string with _(...).
503 For example, suppose LC_ALL is unset, LC_TIME="POSIX",
504 and LANG="ko_KR". In that case, POSIX says that LC_TIME
505 determines the format and contents of date and time strings
506 written by date, which means "date" must generate output
507 using the POSIX locale; but adding _() would cause "date"
508 to use a Korean translation of the format. */
509 format = *date_fmt ? date_fmt : "%a %b %e %H:%M:%S %Z %Y";
512 else if (*format == '\0')
518 tm = localtime (&when.tv_sec);
521 char buf[INT_BUFSIZE_BOUND (intmax_t)];
522 error (0, 0, _("time %s is out of range"),
523 (TYPE_SIGNED (time_t)
524 ? imaxtostr (when.tv_sec, buf)
525 : umaxtostr (when.tv_sec, buf)));
533 out = x2nrealloc (out, &out_length, sizeof *out);
535 /* Mark the first byte of the buffer so we can detect the case
536 of nstrftime producing an empty string. Otherwise, this loop
537 would not terminate when date was invoked like this
538 `LANG=de date +%p' on a system with good language support. */
542 setlocale (LC_ALL, "C");
544 done = (nstrftime (out, out_length, format, tm, 0, when.tv_nsec)
548 setlocale (LC_ALL, "");
554 printf ("%s\n", out);