Character
Grep
Grep can match strings. Grep is the embodiment of the computer.
Grep is fast and powerful when a string of characters needs to be matched exactly. But Grep has no way of knowing what the string means.
It is easy to confuse "cat = mammal" for meaning. But from Grep's perspective, it's just c a t = m a m m a l. It can convert it into a = 3, m = 3, t = 1 and t = 1. But it cannot convert it into "cat = pet".
Origin: Unix search tool