date es un comando Linux que sirve para visualizar la hora y fecha del sistema y para configurar dicha hora y fecha. La hora del sistema es la que gestiona el Sistema Operativo y toma como referencia al reloj hardware de la máquina, el cual puede marcar de hecho una hora distinta (ver hwclock).
Ejecutado sin argumentos muestra la hora y fecha actual del sistema:
[root@localhost ~]# date vie ene 4 06:09:45 CET 2008
Formato para visualizar la hora y fecha:
date [OPTION]… [+FORMAT]
Formato para configurar la hora y fecha:
date [-u|–utc|–universal] [MMDDhhmm[[CC]YY][.ss]]
Las opciones son (trascripción del man):
| -d
–date=STRING |
display time described by STRING, not ‘now’ |
| -f
–file=DATEFILE |
like –date once for each line of DATEFILE |
| -r
–reference=FILE |
display the last modification time of FILE |
| -R
–rfc-2822 |
output date and time in RFC 2822 format |
| –rfc-3339=TIMESPEC | output date and time in RFC 3339 format. TIMESPEC=‘date’, ‘seconds’, or ‘ns’ for date and time to the indicated precision. |
| -s
–set=STRING |
set time described by STRING |
| -u
–utc –universal |
-u, –utc, –universal |
| –help | display help and exit |
| –version | output version information and exit |
FORMAT controla la salida, es decir, la forma en que se muestra la fecha y hora. Las secuencias son (trascripción del man):
%% a literal %
%a locale’s abbreviated weekday name (e.g., Sun)
%A locale’s full weekday name (e.g., Sunday)
%b locale’s abbreviated month name (e.g., Jan)
%B locale’s full month name (e.g., January)
%c locale’s date and time (e.g., Thu Mar 3 23:05:25 2005)
%C century; like %Y, except omit last two digits (e.g., 21)
%d day of month (e.g, 01)
%D date; same as %m/%d/%y
%e day of month, space padded; same as %_d
%F full date; same as %Y-%m-%d
%g last two digits of year of ISO week number (see %G)
%G year of ISO week number (see %V); normally useful only with %V
%h same as %b
%H hour (00..23)
%I hour (01..12)
%j day of year (001..366)
%k hour ( 0..23)
%l hour ( 1..12)
%m month (01..12)
%M minute (00..59)
%n a newline
%N nanoseconds (000000000..999999999)
%p locale’s equivalent of either AM or PM; blank if not known
%P like %p, but lower case
%r locale’s 12-hour clock time (e.g., 11:11:04 PM)
%R 24-hour hour and minute; same as %H:%M
%s seconds since 1970-01-01 00:00:00 UTC
%S second (00..60)
%t a tab
%T time; same as %H:%M:%S
%u day of week (1..7); 1 is Monday
%U week number of year, with Sunday as first day of week (00..53)
%V ISO week number, with Monday as first day of week (01..53)
%w day of week (0..6); 0 is Sunday
%W week number of year, with Monday as first day of week (00..53)
%x locale’s date representation (e.g., 12/31/99)
%X locale’s time representation (e.g., 23:13:48)
%y last two digits of year (00..99)
%Y year
%z +hhmm numeric timezone (e.g., -0400)
%:z +hh:mm numeric timezone (e.g., -04:00)
%::z +hh:mm:ss numeric time zone (e.g., -04:00:00)
%:::z numeric time zone with : to necessary precision (e.g., -04, +05:30)
%Z alphabetic time zone abbreviation (e.g., EDT)
Por defecto la fecha completa los campos numéricos con ceros.
Ejemplos:
Para poner fecha:
[root@localhost ~]# date -s "7/19/2010 15:26:00" lun jul 19 15:26:00 CEST 2010
Visualizar la fecha:
[root@localhost ~]# date '+Fecha: %m/%d/%y%nHora:%H:%M:%S' Fecha: 07/19/10 Hora:15:27:30