Gnu/coreutils/Calendar-date-items
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29.2 Calendar date items
A calendar date item specifies a day of the year. It is specified differently, depending on whether the month is specified numerically or literally. All these strings specify the same calendar date:
1972-09-24 # ISO 8601. 72-9-24 # Assume 19xx for 69 through 99, # 20xx for 00 through 68. 72-09-24 # Leading zeros are ignored. 9/24/72 # Common U.S. writing. 24 September 1972 24 Sept 72 # September has a special abbreviation. 24 Sep 72 # Three-letter abbreviations always allowed. Sep 24, 1972 24-sep-72 24sep72
The year can also be omitted. In this case, the last specified year is used, or the current year if none. For example:
9/24 sep 24
Here are the rules.
For numeric months, the ISO 8601 format
‘year-month-day
’ is allowed, where year
is
any positive number, month
is a number between 01 and 12, and
day
is a number between 01 and 31. A leading zero must be present
if a number is less than ten. If year
is 68 or smaller, then 2000
is added to it; otherwise, if year
is less than 100,
then 1900 is added to it. The construct
‘month/day/year
’, popular in the United States,
is accepted. Also ‘month/day
’, omitting the year.
Literal months may be spelled out in full: ‘January
’,
‘February
’, ‘March
’, ‘April
’, ‘May
’, ‘June
’,
‘July
’, ‘August
’, ‘September
’, ‘October
’,
‘November
’ or ‘December
’. Literal months may be abbreviated
to their first three letters, possibly followed by an abbreviating dot.
It is also permitted to write ‘Sept
’ instead of ‘September
’.
When months are written literally, the calendar date may be given as any of the following:
day month year day month month day year day-month-year
Or, omitting the year:
month day
Next: Time of day items, Previous: General date syntax, Up: Date input formats [Contents][Index]