Use the --calendar option to create a calendar dialog.  returns the selected date to standard error. If no date is specified on the command line, the dialog uses the current date.
The calendar dialog supports the following options:
--text=textSpecifies the text that is displayed in the calendar dialog.--day=daySpecifies the day that is selected in the calendar dialog. day must be a number between 1 and 31 inclusive.
--month=monthSpecifies the month that is selected in the calendar dialog. month must be a number between 1 and 12 inclusive.
--year=yearSpecifies the year that is selected in the calendar dialog.--date-format=formatSpecifies the format that is returned from the calendar dialog after date selection. The default format depends on your locale. format must be a format that is acceptable to the strftime function, for example %A %d/%m/%y.
The following example script shows how to create a calendar dialog:
#!/bin/sh
if zenity --calendar \
--title="Select a Date" \
--text="Click on a date to select that date." \
--day=10 --month=8 --year=2004
then echo $?
else echo "No date selected"
fi
calendar dialog example
