I need to know what is the differance between ioscan comand and search command ,in addition I search in your site for more details on ioscan command but I found nothing.
First, if you did a search on ioscan, you would have found quite a few threads with that subject.
Second, what OS is this you are using? Hard to tell since some UNIX don't have a ioscan (HP and AIX do - Solaris doesn't). And some don't have a search command. Giving enough (and basic ) information will get you an answer more quickly.
And third, this forum "What's on your mind" is more for chatting about things other than UNIX - you should look at the different forums and try to put your questions in one that fits.