Here's the scoop: awhile is an adverb. It means "for an unspecified amount of time." A while is a noun, like a puppy or an hour. Note the use of the article a. Any time you use a prepositional phrase, such as in a while or for a while, it's always a while, because the object of a preposition has to be a noun. Here are a few examples:
I'm going to read awhile.
Please think awhile before you respond.
I'm going to read for a while.
It took me a while to realize the truth.
Notice that if you can substitute in another adverb, like silently, you want awhile, as in example one and two. If you can substitute in an hour, as in example three and four, you want a while.
I find that I use a while almost exclusively when I write:
“Something I should have done a while ago.” Jason leans back and nods at his handiwork. “This is your jersey.” His hands linger for a moment on my waist. "It's always been yours." --Paula Stokes, The Art of Lainey
Bee reclines on my bed. “Elaine Mitchell. I’ve been your friend for ten years. You’re family. Maybe I want to strangle you every once in a while, but I will never tell you to get lost, okay? I would miss you too much.”
--Paula Stokes, The Art of Lainey
What about you? Do you use both awhile and a while? Did you know the difference? Do you have a grammar or writing question you want MCS to investigate?