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 (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))
323 iso_8601_format = (optarg
324 ? XARGMATCH ("--iso-8601", optarg,
325 time_spec_string, time_spec)
335 set_datestr = optarg;
339 /* POSIX says that `date -u' is equivalent to setting the TZ
340 environment variable, so this option should do nothing other
342 if (putenv ("TZ=UTC0") != 0)
346 case_GETOPT_HELP_CHAR;
347 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
349 usage (EXIT_FAILURE);
352 n_args = argc - optind;
354 option_specified_date = ((datestr ? 1 : 0)
355 + (batch_file ? 1 : 0)
356 + (reference ? 1 : 0));
358 if (option_specified_date > 1)
361 _("the options to specify dates for printing are mutually exclusive"));
362 usage (EXIT_FAILURE);
365 if (set_date && option_specified_date)
368 _("the options to print and set the time may not be used together"));
369 usage (EXIT_FAILURE);
374 error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
375 usage (EXIT_FAILURE);
378 if ((set_date || option_specified_date)
379 && n_args == 1 && argv[optind][0] != '+')
382 the argument `%s' lacks a leading `+';\n\
383 When using an option to specify date(s), any non-option\n\
384 argument must be a format string beginning with `+'."),
386 usage (EXIT_FAILURE);
389 /* Simply ignore --rfc-2822 if specified when setting the date. */
390 if (rfc_format && !set_date && n_args > 0)
393 _("a format string may not be specified when using\
394 the --rfc-2822 (-R) option"));
395 usage (EXIT_FAILURE);
399 datestr = set_datestr;
401 if (batch_file != NULL)
402 ok = batch_convert (batch_file, (n_args == 1 ? argv[optind] + 1 : NULL));
405 bool valid_date = true;
408 if (!option_specified_date && !set_date)
410 if (n_args == 1 && argv[optind][0] != '+')
412 /* Prepare to set system clock to the specified date/time
413 given in the POSIX-format. */
415 datestr = argv[optind];
416 valid_date = posixtime (&when.tv_sec,
419 | PDS_CENTURY | PDS_SECONDS));
420 when.tv_nsec = 0; /* FIXME: posixtime should set this. */
425 /* Prepare to print the current date/time. */
426 datestr = _("undefined");
428 format = (n_args == 1 ? argv[optind] + 1 : NULL);
433 /* (option_specified_date || set_date) */
434 if (reference != NULL)
436 if (stat (reference, &refstats))
437 error (EXIT_FAILURE, errno, "%s", reference);
438 when.tv_sec = refstats.st_mtime;
439 when.tv_nsec = TIMESPEC_NS (refstats.st_mtim);
443 valid_date = get_date (&when, datestr, NULL);
446 format = (n_args == 1 ? argv[optind] + 1 : NULL);
450 error (EXIT_FAILURE, 0, _("invalid date `%s'"), datestr);
454 /* Set the system clock to the specified date, then regardless of
455 the success of that operation, format and print that date. */
456 if (settime (&when) != 0)
458 error (0, errno, _("cannot set date"));
463 ok &= show_date (format, when);
466 exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
469 /* Display the date and/or time in WHEN according to the format specified
470 in FORMAT, followed by a newline. If FORMAT is NULL, use the
471 standard output format (ctime style but with a timezone inserted).
472 Return true if successful. */
475 show_date (const char *format, struct timespec when)
479 size_t out_length = 0;
480 /* ISO 8601 formats. See below regarding %z */
481 static char const * const iso_format_string[] =
486 "%Y-%m-%dT%H:%M:%S%z",
487 "%Y-%m-%dT%H:%M:%S,%N%z"
493 format = "%a, %d %b %Y %H:%M:%S %z";
494 else if (iso_8601_format)
495 format = iso_format_string[iso_8601_format - 1];
498 char *date_fmt = DATE_FMT_LANGINFO ();
499 /* Do not wrap the following literal format string with _(...).
500 For example, suppose LC_ALL is unset, LC_TIME="POSIX",
501 and LANG="ko_KR". In that case, POSIX says that LC_TIME
502 determines the format and contents of date and time strings
503 written by date, which means "date" must generate output
504 using the POSIX locale; but adding _() would cause "date"
505 to use a Korean translation of the format. */
506 format = *date_fmt ? date_fmt : "%a %b %e %H:%M:%S %Z %Y";
509 else if (*format == '\0')
515 tm = localtime (&when.tv_sec);
518 char buf[INT_BUFSIZE_BOUND (intmax_t)];
519 error (0, 0, _("time %s is out of range"),
520 (TYPE_SIGNED (time_t)
521 ? imaxtostr (when.tv_sec, buf)
522 : umaxtostr (when.tv_sec, buf)));
530 out = x2nrealloc (out, &out_length, sizeof *out);
532 /* Mark the first byte of the buffer so we can detect the case
533 of nstrftime producing an empty string. Otherwise, this loop
534 would not terminate when date was invoked like this
535 `LANG=de date +%p' on a system with good language support. */
539 setlocale (LC_ALL, "C");
541 done = (nstrftime (out, out_length, format, tm, 0, when.tv_nsec)
545 setlocale (LC_ALL, "");
551 printf ("%s\n", out);