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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 David MacKenzie <djm@gnu.ai.mit.edu> */
23 #include <sys/types.h>
24 #if HAVE_LANGINFO_CODESET
25 # include <langinfo.h>
38 /* The official name of this program (e.g., no `g' prefix). */
39 #define PROGRAM_NAME "date"
41 #define AUTHORS "David MacKenzie"
45 static bool show_date (const char *format, struct timespec when);
49 /* display only the date: 1999-03-25 */
51 /* display date and hour: 1999-03-25T03-0500 */
53 /* display date, hours, and minutes: 1999-03-25T03:23-0500 */
55 /* display date, hours, minutes, and seconds: 1999-03-25T03:23:14-0500 */
57 /* similar, but display nanoseconds: 1999-03-25T03:23:14,123456789-0500 */
61 static char const *const time_spec_string[] =
63 "date", "hours", "minutes", "seconds", "ns", NULL
66 static enum Time_spec const time_spec[] =
68 TIME_SPEC_DATE, TIME_SPEC_HOURS, TIME_SPEC_MINUTES, TIME_SPEC_SECONDS,
72 /* The name this program was run with, for error messages. */
75 /* If nonzero, display an ISO 8601 format date/time string */
76 static int iso_8601_format = 0;
78 /* If true, display time in RFC-(2)822 format for mail or news. */
79 static bool rfc_format = false;
81 static char const short_options[] = "d:f:I::r:Rs:u";
83 static struct option const long_options[] =
85 {"date", required_argument, NULL, 'd'},
86 {"file", required_argument, NULL, 'f'},
87 {"iso-8601", optional_argument, NULL, 'I'},
88 {"reference", required_argument, NULL, 'r'},
89 {"rfc-822", no_argument, NULL, 'R'},
90 {"rfc-2822", no_argument, NULL, 'R'},
91 {"set", required_argument, NULL, 's'},
92 {"uct", no_argument, NULL, 'u'},
93 {"utc", no_argument, NULL, 'u'},
94 {"universal", no_argument, NULL, 'u'},
95 {GETOPT_HELP_OPTION_DECL},
96 {GETOPT_VERSION_OPTION_DECL},
101 # define TZSET tzset ()
103 # define TZSET /* empty */
107 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
109 # define DATE_FMT_LANGINFO() ""
115 if (status != EXIT_SUCCESS)
116 fprintf (stderr, _("Try `%s --help' for more information.\n"),
121 Usage: %s [OPTION]... [+FORMAT]\n\
122 or: %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
124 program_name, program_name);
126 Display the current time in the given FORMAT, or set the system date.\n\
128 -d, --date=STRING display time described by STRING, not `now'\n\
129 -f, --file=DATEFILE like --date once for each line of DATEFILE\n\
130 -I[TIMESPEC], --iso-8601[=TIMESPEC] output date/time in ISO 8601 format.\n\
131 TIMESPEC=`date' for date only (the default),\n\
132 `hours', `minutes', `seconds', or `ns' for date and\n\
133 time to the indicated precision.\n\
136 -r, --reference=FILE display the last modification time of FILE\n\
137 -R, --rfc-2822 output RFC-2822 compliant date string\n\
138 -s, --set=STRING set time described by STRING\n\
139 -u, --utc, --universal print or set Coordinated Universal Time\n\
141 fputs (HELP_OPTION_DESCRIPTION, stdout);
142 fputs (VERSION_OPTION_DESCRIPTION, stdout);
145 FORMAT controls the output. The only valid option for the second form\n\
146 specifies Coordinated Universal Time. Interpreted sequences are:\n\
149 %a locale's abbreviated weekday name (e.g., Sun)\n\
152 %A locale's full weekday name (e.g., Sunday)\n\
153 %b locale's abbreviated month name (e.g., Jan)\n\
154 %B locale's full month name (e.g., January)\n\
155 %c locale's date and time (e.g., Thu Mar 3 23:05:25 2005)\n\
158 %C century; like %Y, except omit last two digits (e.g., 21)\n\
159 %d day of month (e.g, 01)\n\
160 %D date; same as %m/%d/%y\n\
161 %e day of month, space padded; same as %_d\n\
164 %F full date; same as %Y-%m-%d\n\
165 %g the last two digits of the year corresponding to the %V week number\n\
166 %G the year corresponding to the %V week number\n\
172 %j day of year (001..366)\n\
178 %M minute (00..59)\n\
182 %N nanoseconds (000000000..999999999)\n\
183 %p locale's equivalent of either AM or PM; blank if not known\n\
184 %P like %p, but lower case\n\
185 %r locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
186 %R 24-hour hour and minute; same as %H:%M\n\
187 %s seconds since 1970-01-01 00:00:00 UTC\n\
190 %S second (00..60)\n\
192 %T time; same as %H:%M:%S\n\
193 %u day of week (1..7); 1 is Monday\n\
196 %U week number of year with Sunday as first day of week (00..53)\n\
197 %V week number of year with Monday as first day of week (01..53)\n\
198 %w day of week (0..6); 0 is Sunday\n\
199 %W week number of year with Monday as first day of week (00..53)\n\
202 %x locale's date representation (e.g., 12/31/99)\n\
203 %X locale's time representation (e.g., 23:13:48)\n\
204 %y last two digits of year (00..99)\n\
208 %z numeric timezone (e.g., -0400)\n\
209 %Z alphabetic time zone abbreviation (e.g., EDT)\n\
211 By default, date pads numeric fields with zeroes.\n\
212 The following optional flags may follow `%':\n\
214 - (hyphen) do not pad the field\n\
215 _ (underscore) pad with spaces\n\
216 0 (zero) pad with zeros\n\
217 ^ use upper case if possible\n\
218 # use opposite case if possible\n\
222 After any flags comes an optional field width, as a decimal number;\n\
223 then an optional modifier, which is either\n\
224 E to use the locale's alternate representations if available, or\n\
225 O to use the locale's alternate numeric symbols if available.\n\
227 printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
232 /* Parse each line in INPUT_FILENAME as with --date and display each
233 resulting time and date. If the file cannot be opened, tell why
234 then exit. Issue a diagnostic for any lines that cannot be parsed.
235 Return true if successful. */
238 batch_convert (const char *input_filename, const char *format)
244 struct timespec when;
246 if (STREQ (input_filename, "-"))
248 input_filename = _("standard input");
253 in_stream = fopen (input_filename, "r");
254 if (in_stream == NULL)
256 error (EXIT_FAILURE, errno, "%s", quote (input_filename));
265 ssize_t line_length = getline (&line, &buflen, in_stream);
268 /* FIXME: detect/handle error here. */
272 if (! get_date (&when, line, NULL))
274 if (line[line_length - 1] == '\n')
275 line[line_length - 1] = '\0';
276 error (0, 0, _("invalid date %s"), quote (line));
281 ok &= show_date (format, when);
285 if (fclose (in_stream) == EOF)
286 error (EXIT_FAILURE, errno, "%s", quote (input_filename));
294 main (int argc, char **argv)
297 const char *datestr = NULL;
298 const char *set_datestr = NULL;
299 struct timespec when;
300 bool set_date = false;
302 char *batch_file = NULL;
303 char *reference = NULL;
304 struct stat refstats;
307 int option_specified_date;
309 initialize_main (&argc, &argv);
310 program_name = argv[0];
311 setlocale (LC_ALL, "");
312 bindtextdomain (PACKAGE, LOCALEDIR);
313 textdomain (PACKAGE);
315 atexit (close_stdout);
317 while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
328 iso_8601_format = (optarg
329 ? XARGMATCH ("--iso-8601", optarg,
330 time_spec_string, time_spec)
340 set_datestr = optarg;
344 /* POSIX says that `date -u' is equivalent to setting the TZ
345 environment variable, so this option should do nothing other
347 if (putenv ("TZ=UTC0") != 0)
351 case_GETOPT_HELP_CHAR;
352 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
354 usage (EXIT_FAILURE);
357 n_args = argc - optind;
359 option_specified_date = ((datestr ? 1 : 0)
360 + (batch_file ? 1 : 0)
361 + (reference ? 1 : 0));
363 if (option_specified_date > 1)
366 _("the options to specify dates for printing are mutually exclusive"));
367 usage (EXIT_FAILURE);
370 if (set_date && option_specified_date)
373 _("the options to print and set the time may not be used together"));
374 usage (EXIT_FAILURE);
379 error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
380 usage (EXIT_FAILURE);
383 if ((set_date || option_specified_date)
384 && n_args == 1 && argv[optind][0] != '+')
387 the argument %s lacks a leading `+';\n\
388 When using an option to specify date(s), any non-option\n\
389 argument must be a format string beginning with `+'."),
390 quote (argv[optind]));
391 usage (EXIT_FAILURE);
394 /* Simply ignore --rfc-2822 if specified when setting the date. */
395 if (rfc_format && !set_date && n_args > 0)
398 _("a format string may not be specified when using\
399 the --rfc-2822 (-R) option"));
400 usage (EXIT_FAILURE);
404 datestr = set_datestr;
406 if (batch_file != NULL)
407 ok = batch_convert (batch_file, (n_args == 1 ? argv[optind] + 1 : NULL));
410 bool valid_date = true;
413 if (!option_specified_date && !set_date)
415 if (n_args == 1 && argv[optind][0] != '+')
417 /* Prepare to set system clock to the specified date/time
418 given in the POSIX-format. */
420 datestr = argv[optind];
421 valid_date = posixtime (&when.tv_sec,
424 | PDS_CENTURY | PDS_SECONDS));
425 when.tv_nsec = 0; /* FIXME: posixtime should set this. */
430 /* Prepare to print the current date/time. */
431 datestr = _("undefined");
433 format = (n_args == 1 ? argv[optind] + 1 : NULL);
438 /* (option_specified_date || set_date) */
439 if (reference != NULL)
441 if (stat (reference, &refstats))
442 error (EXIT_FAILURE, errno, "%s", reference);
443 when.tv_sec = refstats.st_mtime;
444 when.tv_nsec = TIMESPEC_NS (refstats.st_mtim);
448 valid_date = get_date (&when, datestr, NULL);
451 format = (n_args == 1 ? argv[optind] + 1 : NULL);
455 error (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
459 /* Set the system clock to the specified date, then regardless of
460 the success of that operation, format and print that date. */
461 if (settime (&when) != 0)
463 error (0, errno, _("cannot set date"));
468 ok &= show_date (format, when);
471 exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
474 /* Display the date and/or time in WHEN according to the format specified
475 in FORMAT, followed by a newline. If FORMAT is NULL, use the
476 standard output format (ctime style but with a timezone inserted).
477 Return true if successful. */
480 show_date (const char *format, struct timespec when)
484 size_t out_length = 0;
485 /* ISO 8601 formats. See below regarding %z */
486 static char const * const iso_format_string[] =
491 "%Y-%m-%dT%H:%M:%S%z",
492 "%Y-%m-%dT%H:%M:%S,%N%z"
498 format = "%a, %d %b %Y %H:%M:%S %z";
499 else if (iso_8601_format)
500 format = iso_format_string[iso_8601_format - 1];
503 char *date_fmt = DATE_FMT_LANGINFO ();
504 /* Do not wrap the following literal format string with _(...).
505 For example, suppose LC_ALL is unset, LC_TIME="POSIX",
506 and LANG="ko_KR". In that case, POSIX says that LC_TIME
507 determines the format and contents of date and time strings
508 written by date, which means "date" must generate output
509 using the POSIX locale; but adding _() would cause "date"
510 to use a Korean translation of the format. */
511 format = *date_fmt ? date_fmt : "%a %b %e %H:%M:%S %Z %Y";
514 else if (*format == '\0')
520 tm = localtime (&when.tv_sec);
523 char buf[INT_BUFSIZE_BOUND (intmax_t)];
524 error (0, 0, _("time %s is out of range"),
525 (TYPE_SIGNED (time_t)
526 ? imaxtostr (when.tv_sec, buf)
527 : umaxtostr (when.tv_sec, buf)));
535 out = x2nrealloc (out, &out_length, sizeof *out);
537 /* Mark the first byte of the buffer so we can detect the case
538 of nstrftime producing an empty string. Otherwise, this loop
539 would not terminate when date was invoked like this
540 `LANG=de date +%p' on a system with good language support. */
544 setlocale (LC_ALL, "C");
546 done = (nstrftime (out, out_length, format, tm, 0, when.tv_nsec)
550 setlocale (LC_ALL, "");
556 printf ("%s\n", out);