check [item] check bacta check parts
This command tells you a bunch of useful info about an object or being:
If you use it on a toolbox or medkit, it will show you how much more use you can get out of the item. If if you specify 'bacta' or 'parts', it will show you the total amount available to you.
Using check on droids will tell you if you can command the droid.
For bounty hunters, it will also show if the item can be used as a modification in their armor.
Using check on a monster will show you information about how difficult that monster will be to fight (<consider> info).
You can use it on items in a shop by specifying 'in shop' after the item name.