I saw a similar small shell in C as a tutorial but it was from a book made in the 1980s on unix programming. Been wondering what that book was ever since becaus

I saw a similar small shell in C as a tutorial but it was from a book made in the 1980s on unix programming. Been wondering what that book was ever since because it was just something sitting around at a job that I didn't get to read all the way through, but it really made things click finally