How do you print the days until a deadline from the command line?

I have an upcoming deadline on Nov. 1st, 2011, and I want to print the days until the deadline every time I open Terminal on my MacBook Pro. I've added this to my .profile:

python -c "from datetime import date; print '%s days until deadline.' % (date(2011,11,1) - date.today()).days"

And this prints 146 days until deadline. whenever I create a new Terminal window.

This s开发者_开发百科olves my need, but I'm wondering what the one-liner looks like in other languages, or if there are ways to use bash or standard posix command line tools to do the same task.

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echo $(expr '(' $(date -d 2011/11/1 +%s) - $(date +%s) + 86399 ')' / 86400) " days until deadline"

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Using awk you can do:

echo "2011 11 01" | awk '{dt=mktime($0 " 00 00 00")-systime(); print int(dt/86400) " days";}'

OUTPUT (as of 8th June 2011)

145 days

Update (to get time difference rounded use below code)

awk '{dt=mktime($0 " 00 00 00")-systime(); d=dt/86400+0.5; printf("%d\n",d);}'