Libra (ability)

Scan, sometimes translated as Peep, is a recurring White Magic spell in the series. It displays an enemy's stats, strengths, and weaknesses. In the later (3D) installments in the series, one could move the Scanned enemy around to see it from all sides.

Final Fantasy IV
The spell was translated as Peep. It costs only 1 MP to cast, and was one of the few spells Cecil could use, and Cid could use a command ability called Peep.

Final Fantasy V
Scan was a Level 1 White Magic spell, purchased in Tule

Final Fantasy VI
Scan could only be taught by the Esper Kirin at a rate of X5. Celes learns it naturally. It costs 5 MP to cast.

Final Fantasy VII
The Sense Materia worked similar to Scan.

Final Fantasy VIII
Scan was a magic that could be used to see enemies stats. It could also be used to see the enemy or teammate in 360 degrees, but in the case of Selphie, you could not go up or down for she was in a small dress.

Final Fantasy IX
Scan was one of the few White Magic spells only Garnet can use.

Final Fantasy X
Scan is located in Kimahri's section of the Sphere Grid.

Final Fantasy XII
In Final Fantasy XII a similar ability called Libra appeared, and in addition to scanning foes, could reveal traps in the floor.