doc: remove older ChangeLog items
[coreutils.git] / src / date.c
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1 /* date - print or set the system date and time
2 Copyright (C) 1989-2024 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 3 of the License, or
7 (at your option) any later version.
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, see <https://www.gnu.org/licenses/>.
17 David MacKenzie <djm@gnu.ai.mit.edu> */
19 #include <config.h>
20 #include <stdio.h>
21 #include <getopt.h>
22 #include <sys/types.h>
23 #if HAVE_LANGINFO_CODESET
24 # include <langinfo.h>
25 #endif
27 #include "system.h"
28 #include "argmatch.h"
29 #include "parse-datetime.h"
30 #include "posixtm.h"
31 #include "quote.h"
32 #include "stat-time.h"
33 #include "fprintftime.h"
35 /* The official name of this program (e.g., no 'g' prefix). */
36 #define PROGRAM_NAME "date"
38 #define AUTHORS proper_name ("David MacKenzie")
40 static bool show_date (char const *, struct timespec, timezone_t);
42 enum Time_spec
44 /* Display only the date. */
45 TIME_SPEC_DATE,
46 /* Display date, hours, minutes, and seconds. */
47 TIME_SPEC_SECONDS,
48 /* Similar, but display nanoseconds. */
49 TIME_SPEC_NS,
51 /* Put these last, since they aren't valid for --rfc-3339. */
53 /* Display date and hour. */
54 TIME_SPEC_HOURS,
55 /* Display date, hours, and minutes. */
56 TIME_SPEC_MINUTES
59 static char const *const time_spec_string[] =
61 /* Put "hours" and "minutes" first, since they aren't valid for
62 --rfc-3339. */
63 "hours", "minutes",
64 "date", "seconds", "ns", nullptr
66 static enum Time_spec const time_spec[] =
68 TIME_SPEC_HOURS, TIME_SPEC_MINUTES,
69 TIME_SPEC_DATE, TIME_SPEC_SECONDS, TIME_SPEC_NS
71 ARGMATCH_VERIFY (time_spec_string, time_spec);
73 /* A format suitable for Internet RFCs 5322, 2822, and 822. */
74 static char const rfc_email_format[] = "%a, %d %b %Y %H:%M:%S %z";
76 /* For long options that have no equivalent short option, use a
77 non-character as a pseudo short option, starting with CHAR_MAX + 1. */
78 enum
80 DEBUG_DATE_PARSING_OPTION = CHAR_MAX + 1,
81 RESOLUTION_OPTION,
82 RFC_3339_OPTION
85 static char const short_options[] = "d:f:I::r:Rs:u";
87 static struct option const long_options[] =
89 {"date", required_argument, nullptr, 'd'},
90 {"debug", no_argument, nullptr, DEBUG_DATE_PARSING_OPTION},
91 {"file", required_argument, nullptr, 'f'},
92 {"iso-8601", optional_argument, nullptr, 'I'},
93 {"reference", required_argument, nullptr, 'r'},
94 {"resolution", no_argument, nullptr, RESOLUTION_OPTION},
95 {"rfc-email", no_argument, nullptr, 'R'},
96 {"rfc-822", no_argument, nullptr, 'R'},
97 {"rfc-2822", no_argument, nullptr, 'R'},
98 {"rfc-3339", required_argument, nullptr, RFC_3339_OPTION},
99 {"set", required_argument, nullptr, 's'},
100 {"uct", no_argument, nullptr, 'u'},
101 {"utc", no_argument, nullptr, 'u'},
102 {"universal", no_argument, nullptr, 'u'},
103 {GETOPT_HELP_OPTION_DECL},
104 {GETOPT_VERSION_OPTION_DECL},
105 {nullptr, 0, nullptr, 0}
108 /* flags for parse_datetime2 */
109 static unsigned int parse_datetime_flags;
111 #if LOCALTIME_CACHE
112 # define TZSET tzset ()
113 #else
114 # define TZSET /* empty */
115 #endif
117 #ifdef _DATE_FMT
118 # define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
119 #else
120 # define DATE_FMT_LANGINFO() ""
121 #endif
123 void
124 usage (int status)
126 if (status != EXIT_SUCCESS)
127 emit_try_help ();
128 else
130 printf (_("\
131 Usage: %s [OPTION]... [+FORMAT]\n\
132 or: %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
134 program_name, program_name);
135 fputs (_("\
136 Display date and time in the given FORMAT.\n\
137 With -s, or with [MMDDhhmm[[CC]YY][.ss]], set the date and time.\n\
138 "), stdout);
140 emit_mandatory_arg_note ();
142 fputs (_("\
143 -d, --date=STRING display time described by STRING, not 'now'\n\
144 "), stdout);
145 fputs (_("\
146 --debug annotate the parsed date,\n\
147 and warn about questionable usage to stderr\n\
148 "), stdout);
149 fputs (_("\
150 -f, --file=DATEFILE like --date; once for each line of DATEFILE\n\
151 "), stdout);
152 fputs (_("\
153 -I[FMT], --iso-8601[=FMT] output date/time in ISO 8601 format.\n\
154 FMT='date' for date only (the default),\n\
155 'hours', 'minutes', 'seconds', or 'ns'\n\
156 for date and time to the indicated precision.\n\
157 Example: 2006-08-14T02:34:56-06:00\n\
158 "), stdout);
159 fputs (_("\
160 --resolution output the available resolution of timestamps\n\
161 Example: 0.000000001\n\
162 "), stdout);
163 fputs (_("\
164 -R, --rfc-email output date and time in RFC 5322 format.\n\
165 Example: Mon, 14 Aug 2006 02:34:56 -0600\n\
166 "), stdout);
167 fputs (_("\
168 --rfc-3339=FMT output date/time in RFC 3339 format.\n\
169 FMT='date', 'seconds', or 'ns'\n\
170 for date and time to the indicated precision.\n\
171 Example: 2006-08-14 02:34:56-06:00\n\
172 "), stdout);
173 fputs (_("\
174 -r, --reference=FILE display the last modification time of FILE\n\
175 "), stdout);
176 fputs (_("\
177 -s, --set=STRING set time described by STRING\n\
178 -u, --utc, --universal print or set Coordinated Universal Time (UTC)\n\
179 "), stdout);
180 fputs (HELP_OPTION_DESCRIPTION, stdout);
181 fputs (VERSION_OPTION_DESCRIPTION, stdout);
182 fputs (_("\
184 All options that specify the date to display are mutually exclusive.\n\
185 I.e.: --date, --file, --reference, --resolution.\n\
186 "), stdout);
187 fputs (_("\
189 FORMAT controls the output. Interpreted sequences are:\n\
191 %% a literal %\n\
192 %a locale's abbreviated weekday name (e.g., Sun)\n\
193 "), stdout);
194 fputs (_("\
195 %A locale's full weekday name (e.g., Sunday)\n\
196 %b locale's abbreviated month name (e.g., Jan)\n\
197 %B locale's full month name (e.g., January)\n\
198 %c locale's date and time (e.g., Thu Mar 3 23:05:25 2005)\n\
199 "), stdout);
200 fputs (_("\
201 %C century; like %Y, except omit last two digits (e.g., 20)\n\
202 %d day of month (e.g., 01)\n\
203 %D date; same as %m/%d/%y\n\
204 %e day of month, space padded; same as %_d\n\
205 "), stdout);
206 fputs (_("\
207 %F full date; like %+4Y-%m-%d\n\
208 %g last two digits of year of ISO week number (see %G)\n\
209 %G year of ISO week number (see %V); normally useful only with %V\n\
210 "), stdout);
211 fputs (_("\
212 %h same as %b\n\
213 %H hour (00..23)\n\
214 %I hour (01..12)\n\
215 %j day of year (001..366)\n\
216 "), stdout);
217 fputs (_("\
218 %k hour, space padded ( 0..23); same as %_H\n\
219 %l hour, space padded ( 1..12); same as %_I\n\
220 %m month (01..12)\n\
221 %M minute (00..59)\n\
222 "), stdout);
223 fputs (_("\
224 %n a newline\n\
225 %N nanoseconds (000000000..999999999)\n\
226 %p locale's equivalent of either AM or PM; blank if not known\n\
227 %P like %p, but lower case\n\
228 %q quarter of year (1..4)\n\
229 %r locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
230 %R 24-hour hour and minute; same as %H:%M\n\
231 %s seconds since the Epoch (1970-01-01 00:00 UTC)\n\
232 "), stdout);
233 fputs (_("\
234 %S second (00..60)\n\
235 %t a tab\n\
236 %T time; same as %H:%M:%S\n\
237 %u day of week (1..7); 1 is Monday\n\
238 "), stdout);
239 fputs (_("\
240 %U week number of year, with Sunday as first day of week (00..53)\n\
241 %V ISO week number, with Monday as first day of week (01..53)\n\
242 %w day of week (0..6); 0 is Sunday\n\
243 %W week number of year, with Monday as first day of week (00..53)\n\
244 "), stdout);
245 fputs (_("\
246 %x locale's date representation (e.g., 12/31/99)\n\
247 %X locale's time representation (e.g., 23:13:48)\n\
248 %y last two digits of year (00..99)\n\
249 %Y year\n\
250 "), stdout);
251 fputs (_("\
252 %z +hhmm numeric time zone (e.g., -0400)\n\
253 %:z +hh:mm numeric time zone (e.g., -04:00)\n\
254 %::z +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
255 %:::z numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
256 %Z alphabetic time zone abbreviation (e.g., EDT)\n\
258 By default, date pads numeric fields with zeroes.\n\
259 "), stdout);
260 fputs (_("\
261 The following optional flags may follow '%':\n\
263 - (hyphen) do not pad the field\n\
264 _ (underscore) pad with spaces\n\
265 0 (zero) pad with zeros\n\
266 + pad with zeros, and put '+' before future years with >4 digits\n\
267 ^ use upper case if possible\n\
268 # use opposite case if possible\n\
269 "), stdout);
270 fputs (_("\
272 After any flags comes an optional field width, as a decimal number;\n\
273 then an optional modifier, which is either\n\
274 E to use the locale's alternate representations if available, or\n\
275 O to use the locale's alternate numeric symbols if available.\n\
276 "), stdout);
277 fputs (_("\
279 Examples:\n\
280 Convert seconds since the Epoch (1970-01-01 UTC) to a date\n\
281 $ date --date='@2147483647'\n\
283 Show the time on the west coast of the US (use tzselect(1) to find TZ)\n\
284 $ TZ='America/Los_Angeles' date\n\
286 Show the local time for 9AM next Friday on the west coast of the US\n\
287 $ date --date='TZ=\"America/Los_Angeles\" 09:00 next Fri'\n\
288 "), stdout);
289 emit_ancillary_info (PROGRAM_NAME);
291 exit (status);
294 /* Yield the number of decimal digits needed to output a time with the
295 nanosecond resolution RES, without losing information. */
297 ATTRIBUTE_CONST
298 static int
299 res_width (long int res)
301 int i = 9;
302 for (long long int r = 1; (r *= 10) <= res; )
303 i--;
304 return i;
307 /* Return a newly allocated copy of FORMAT with each "%-N" adjusted to
308 be "%9N", "%6N", or whatever other resolution is appropriate for
309 the current platform. If no "%-N" appears, return nullptr. */
311 static char *
312 adjust_resolution (char const *format)
314 char *copy = nullptr;
316 for (char const *f = format; *f; f++)
317 if (f[0] == '%')
319 if (f[1] == '-' && f[2] == 'N')
321 if (!copy)
322 copy = xstrdup (format);
323 copy[f + 1 - format] = '0' + res_width (gettime_res ());
324 f += 2;
326 else
327 f += f[1] == '%';
330 return copy;
333 /* Parse each line in INPUT_FILENAME as with --date and display each
334 resulting time and date. If the file cannot be opened, tell why
335 then exit. Issue a diagnostic for any lines that cannot be parsed.
336 Return true if successful. */
338 static bool
339 batch_convert (char const *input_filename, char const *format,
340 timezone_t tz, char const *tzstring)
342 bool ok;
343 FILE *in_stream;
344 char *line;
345 size_t buflen;
346 struct timespec when;
348 if (STREQ (input_filename, "-"))
350 input_filename = _("standard input");
351 in_stream = stdin;
353 else
355 in_stream = fopen (input_filename, "r");
356 if (in_stream == nullptr)
357 error (EXIT_FAILURE, errno, "%s", quotef (input_filename));
360 line = nullptr;
361 buflen = 0;
362 ok = true;
363 while (true)
365 ssize_t line_length = getline (&line, &buflen, in_stream);
366 if (line_length < 0)
368 if (ferror (in_stream))
369 error (EXIT_FAILURE, errno, _("%s: read error"),
370 quotef (input_filename));
371 break;
374 if (! parse_datetime2 (&when, line, nullptr,
375 parse_datetime_flags, tz, tzstring))
377 if (line[line_length - 1] == '\n')
378 line[line_length - 1] = '\0';
379 error (0, 0, _("invalid date %s"), quote (line));
380 ok = false;
382 else
384 ok &= show_date (format, when, tz);
388 if (fclose (in_stream) == EOF)
389 error (EXIT_FAILURE, errno, "%s", quotef (input_filename));
391 free (line);
393 return ok;
397 main (int argc, char **argv)
399 int optc;
400 char const *datestr = nullptr;
401 char const *set_datestr = nullptr;
402 struct timespec when;
403 bool set_date = false;
404 char const *format = nullptr;
405 bool get_resolution = false;
406 char *batch_file = nullptr;
407 char *reference = nullptr;
408 struct stat refstats;
409 bool ok;
410 bool discarded_datestr = false;
411 bool discarded_set_datestr = false;
413 initialize_main (&argc, &argv);
414 set_program_name (argv[0]);
415 setlocale (LC_ALL, "");
416 bindtextdomain (PACKAGE, LOCALEDIR);
417 textdomain (PACKAGE);
419 atexit (close_stdout);
421 while ((optc = getopt_long (argc, argv, short_options, long_options, nullptr))
422 != -1)
424 char const *new_format = nullptr;
426 switch (optc)
428 case 'd':
429 if (datestr)
430 discarded_datestr = true;
431 datestr = optarg;
432 break;
433 case DEBUG_DATE_PARSING_OPTION:
434 parse_datetime_flags |= PARSE_DATETIME_DEBUG;
435 break;
436 case 'f':
437 batch_file = optarg;
438 break;
439 case RESOLUTION_OPTION:
440 get_resolution = true;
441 break;
442 case RFC_3339_OPTION:
444 static char const rfc_3339_format[][32] =
446 "%Y-%m-%d",
447 "%Y-%m-%d %H:%M:%S%:z",
448 "%Y-%m-%d %H:%M:%S.%N%:z"
450 enum Time_spec i =
451 XARGMATCH ("--rfc-3339", optarg,
452 time_spec_string + 2, time_spec + 2);
453 new_format = rfc_3339_format[i];
454 break;
456 case 'I':
458 static char const iso_8601_format[][32] =
460 "%Y-%m-%d",
461 "%Y-%m-%dT%H:%M:%S%:z",
462 "%Y-%m-%dT%H:%M:%S,%N%:z",
463 "%Y-%m-%dT%H%:z",
464 "%Y-%m-%dT%H:%M%:z"
466 enum Time_spec i =
467 (optarg
468 ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
469 : TIME_SPEC_DATE);
470 new_format = iso_8601_format[i];
471 break;
473 case 'r':
474 reference = optarg;
475 break;
476 case 'R':
477 new_format = rfc_email_format;
478 break;
479 case 's':
480 if (set_datestr)
481 discarded_set_datestr = true;
482 set_datestr = optarg;
483 set_date = true;
484 break;
485 case 'u':
486 /* POSIX says that 'date -u' is equivalent to setting the TZ
487 environment variable, so this option should do nothing other
488 than setting TZ. */
489 if (putenv (bad_cast ("TZ=UTC0")) != 0)
490 xalloc_die ();
491 TZSET;
492 break;
493 case_GETOPT_HELP_CHAR;
494 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
495 default:
496 usage (EXIT_FAILURE);
499 if (new_format)
501 if (format)
502 error (EXIT_FAILURE, 0, _("multiple output formats specified"));
503 format = new_format;
507 int option_specified_date = (!!datestr + !!batch_file + !!reference
508 + get_resolution);
510 if (option_specified_date > 1)
512 error (0, 0,
513 _("the options to specify dates for printing are mutually exclusive"));
514 usage (EXIT_FAILURE);
517 if (set_date && option_specified_date)
519 error (0, 0,
520 _("the options to print and set the time may not be used together"));
521 usage (EXIT_FAILURE);
524 if (discarded_datestr && (parse_datetime_flags & PARSE_DATETIME_DEBUG))
525 error (0, 0, _("only using last of multiple -d options"));
527 if (discarded_set_datestr && (parse_datetime_flags & PARSE_DATETIME_DEBUG))
528 error (0, 0, _("only using last of multiple -s options"));
530 if (optind < argc)
532 if (optind + 1 < argc)
534 error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
535 usage (EXIT_FAILURE);
538 if (argv[optind][0] == '+')
540 if (format)
541 error (EXIT_FAILURE, 0, _("multiple output formats specified"));
542 format = argv[optind++] + 1;
544 else if (set_date || option_specified_date)
546 error (0, 0,
547 _("the argument %s lacks a leading '+';\n"
548 "when using an option to specify date(s), any non-option\n"
549 "argument must be a format string beginning with '+'"),
550 quote (argv[optind]));
551 usage (EXIT_FAILURE);
555 if (!format)
557 if (get_resolution)
558 format = "%s.%N";
559 else
561 format = DATE_FMT_LANGINFO ();
563 /* Do not wrap the following literal format string with _(...).
564 For example, suppose LC_ALL is unset, LC_TIME=POSIX,
565 and LANG="ko_KR". In that case, POSIX says that LC_TIME
566 determines the format and contents of date and time strings
567 written by date, which means "date" must generate output
568 using the POSIX locale; but adding _() would cause "date"
569 to use a Korean translation of the format. */
570 if (! *format)
571 format = "%a %b %e %H:%M:%S %Z %Y";
575 char *format_copy = adjust_resolution (format);
576 char const *format_res = format_copy ? format_copy : format;
577 char const *tzstring = getenv ("TZ");
578 timezone_t tz = tzalloc (tzstring);
580 if (batch_file != nullptr)
581 ok = batch_convert (batch_file, format_res, tz, tzstring);
582 else
584 bool valid_date = true;
585 ok = true;
587 if (!option_specified_date && !set_date)
589 if (optind < argc)
591 /* Prepare to set system clock to the specified date/time
592 given in the POSIX-format. */
593 set_date = true;
594 datestr = argv[optind];
595 valid_date = posixtime (&when.tv_sec,
596 datestr,
597 (PDS_TRAILING_YEAR
598 | PDS_CENTURY | PDS_SECONDS));
599 when.tv_nsec = 0; /* FIXME: posixtime should set this. */
601 else
603 /* Prepare to print the current date/time. */
604 gettime (&when);
607 else
609 /* (option_specified_date || set_date) */
610 if (reference != nullptr)
612 if (stat (reference, &refstats) != 0)
613 error (EXIT_FAILURE, errno, "%s", quotef (reference));
614 when = get_stat_mtime (&refstats);
616 else if (get_resolution)
618 long int res = gettime_res ();
619 when.tv_sec = res / TIMESPEC_HZ;
620 when.tv_nsec = res % TIMESPEC_HZ;
622 else
624 if (set_datestr)
625 datestr = set_datestr;
626 valid_date = parse_datetime2 (&when, datestr, nullptr,
627 parse_datetime_flags,
628 tz, tzstring);
632 if (! valid_date)
633 error (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
635 if (set_date)
637 /* Set the system clock to the specified date, then regardless of
638 the success of that operation, format and print that date. */
639 if (settime (&when) != 0)
641 error (0, errno, _("cannot set date"));
642 ok = false;
646 ok &= show_date (format_res, when, tz);
649 main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
652 /* Display the date and/or time in WHEN according to the format specified
653 in FORMAT, followed by a newline. Return true if successful. */
655 static bool
656 show_date (char const *format, struct timespec when, timezone_t tz)
658 struct tm tm;
660 if (parse_datetime_flags & PARSE_DATETIME_DEBUG)
661 error (0, 0, _("output format: %s"), quote (format));
663 if (localtime_rz (tz, &when.tv_sec, &tm))
665 if (format == rfc_email_format)
666 setlocale (LC_TIME, "C");
667 fprintftime (stdout, format, &tm, tz, when.tv_nsec);
668 if (format == rfc_email_format)
669 setlocale (LC_TIME, "");
670 fputc ('\n', stdout);
671 return true;
673 else
675 char buf[INT_BUFSIZE_BOUND (intmax_t)];
676 error (0, 0, _("time %s is out of range"),
677 quote (timetostr (when.tv_sec, buf)));
678 return false;