date command gives no output
Firstly, check your $PATH (run echo $PATH)
If /bin isn't there, then run export PATH=/bin:$PATH

After that run which date and you should see /bin/date

If you still don't have any output, check if date isn't alias (run alias date)
It should say bash: alias: date: not found.  

But in your case it may be alias date='some-command'
If it is, run unalias date and it should fix the problem.

Thanks Allan for the comments with answer.