"wait" does not check that its argument is an integer

The 'wait' command is supposed to take an integer. However, it seems to just use scanf("%d"), as it will accept any word. If it begins with an integer, it will take just the integer part. Otherwise, it will wait for "-1 seconds" (which waits forever). It is also possible to supply any negative number.

It should only accept a non-negative integer.

Check if this sort of parsing is systemic in the command processor, or just applies to 'wait'.