There are several useful ways one may specify which item one hopes to refer
to with a command. Suppose that you had three packs in your inventory,
two traveler's packs and one large leather backpack. The command LOOK IN PACK
would yield unpredictable results, because 'pack' could refer to any of the
three packs. The use of a unique keyword, such as 'large,' would allow
you to specify that you meant the large backpack, unless you had another
'large' item in your inventory. The sure-fire way to look in your large
leather backpack would be to use multiple keywords, grouped by quotes: LOOK
IN 'large leather backpack'. This may not be a worthwhile exercise when just
rummaging through your things, but if buying something from a merchant, or
giving something to an NPC (mobile), it may be prudent indeed.
This leaves the question of what to do with two identical items, say your two
traveler's packs. These may be differentiated by number, as follows: LOOK IN
travelers would look in the first pack (the one you were wearing, if you were
wearing one). To look in the other, you could issue the command LOOK IN
2.travelers
In the case of many of the same item, the same format may be used:
2.parchment, 3.parchment, 4.parchment, etc.