What's different between "look in" and "look at"?
Native speaker’s answer
Rebecca
"Look in" refers to looking inside of something. "Look in" is used here because a file, whether physical or digital, is "closed". Therefore, one can look "inside" of a file. "Look at" refers to looking towards someone or something. Ex: If you look in that box, you will find a present. ("Look in" is used because a "box" is a closed object) Ex: Look at that bird, it has red feathers. ("Look at" is used because one looks towards a bird)