Which command is used to view the contents of a file one screen at a time?

The command used to view the contents of a file one screen at a time is "more." This command allows users to paginate through files, making it easier to read long texts without overwhelming the terminal with content. When you execute "more" followed by a filename, it displays the content one screen's worth at a time, allowing you to use navigation commands (like pressing the spacebar to move to the next page or 'Enter' to scroll line by line) to control your viewing experience.

While the other commands listed also deal with file content, they serve different purposes. The "cat" command concatenates and displays the entire content of a file but does not paginate. The "head" command shows only the first few lines of a file (defaulting to the first 10), while "tail" displays the last few lines. These commands are useful for specific scenarios but do not provide the paginated viewing experience that "more" does.