Number of days in current month

Shell Programming and Scripting
1

I have a homework assignment:

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"Display" the number of days in the current month. For example:
September 1996 has 30 days
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I am trying to just display the head of cal to start the sentence.
eg. cal | head

but it displays the entire calendar.

Help?

2

Have you looked at:
http://www.unix.com/answers-frequently-asked-questions/13785-yesterdays-date-date-arithmetic.html

Also, there is a specific forum for homework. Further homework questions are to be posted there.