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Languguage OS II Version 10-94 (Knowledge Media)(1994).ISO
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shllutil.lha
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shellutils-1.8
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src
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date.c
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1992-05-11
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/* date - print or set the system date and time
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/* Options:
-d DATESTR Display the date DATESTR.
-s DATESTR Set the date to DATESTR.
-u Display or set the date in universal instead of local time.
+FORMAT Specify custom date output format, described below.
MMDDhhmm[[CC]YY][.ss] Set the date in the format described below.
If one non-option argument is given, it is used as the date to which
to set the system clock, and must have the format:
MM month (01..12)
DD day in month (01..31)
hh hour (00..23)
mm minute (00..59)
CC first 2 digits of year (optional, defaults to current) (00..99)
YY last 2 digits of year (optional, defaults to current) (00..99)
ss second (00..61)
If a non-option argument that starts with a `+' is specified, it
is used to control the format in which the date is printed; it
can contain any of the `%' substitutions allowed by the strftime
function. A newline is always added at the end of the output.
David MacKenzie <djm@gnu.ai.mit.edu> */
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#include "system.h"
/* This is portable and avoids bringing in all of the ctype stuff. */
#define isdigit(c) ((c) >= '0' && (c) <= '9')
#ifdef TM_IN_SYS_TIME
#include <sys/time.h>
#else
#include <time.h>
#endif
#ifndef STDC_HEADERS
time_t mktime ();
size_t strftime ();
time_t time ();
#endif
int putenv ();
int stime ();
char *xrealloc ();
time_t get_date ();
time_t posixtime ();
void error ();
void show_date ();
void usage ();
/* putenv string to use Universal Coordinated Time.
POSIX.2 says it should be "TZ=UCT0" or "TZ=GMT0". */
#ifndef TZ_UCT
#if defined(hpux) || defined(__hpux__) || defined(ultrix) || defined(__ultrix__) || defined(USG)
#define TZ_UCT "TZ=GMT0"
#else
#define TZ_UCT "TZ="
#endif
#endif
/* The name this program was run with, for error messages. */
char *program_name;
void
main (argc, argv)
int argc;
char **argv;
{
int optc;
char *datestr = NULL;
time_t when;
int set_date = 0;
int universal_time = 0;
program_name = argv[0];
while ((optc = getopt (argc, argv, "d:s:u")) != EOF)
switch (optc)
{
case 'd':
datestr = optarg;
break;
case 's':
datestr = optarg;
set_date = 1;
break;
case 'u':
universal_time = 1;
break;
default:
usage ();
}
if (argc - optind > 1)
usage ();
if (universal_time && putenv (TZ_UCT) != 0)
error (1, 0, "virtual memory exhausted");
time (&when);
if (datestr)
when = get_date (datestr, NULL);
if (argc - optind == 1 && argv[optind][0] != '+')
{
when = posixtime (argv[optind]);
set_date = 1;
}
if (when == -1)
error (1, 0, "invalid date");
if (set_date && stime (&when) == -1)
error (0, errno, "cannot set date");
if (argc - optind == 1 && argv[optind][0] == '+')
show_date (argv[optind] + 1, when);
else
show_date ((char *) NULL, when);
exit (0);
}
/* Display the date and/or time in WHEN according to the format specified
in FORMAT, followed by a newline. If FORMAT is NULL, use the
standard output format (ctime style but with a timezone inserted). */
void
show_date (format, when)
char *format;
time_t when;
{
struct tm *tm;
char *out = NULL;
size_t out_length = 0;
tm = localtime (&when);
if (format == NULL)
/* Print the date in the default format. Vanilla ANSI C strftime
doesn't support %e, but POSIX requires it. If you don't use
a GNU strftime, make sure yours supports %e. */
format = "%a %b %e %H:%M:%S %Z %Y";
else if (*format == '\0')
{
printf ("\n");
return;
}
do
{
out_length += 200;
out = (char *) xrealloc (out, out_length);
}
while (strftime (out, out_length, format, tm) == 0);
printf ("%s\n", out);
free (out);
}
void
usage ()
{
fprintf (stderr, "\
Usage: %s [-u] [-d datestr] [-s datestr] [+FORMAT] [MMDDhhmm[[CC]YY][.ss]]\n",
program_name);
exit (1);
}