diff - Wikipedia diff is a shell command that compares the content of files and reports differences The term diff is also used to identify the output of the command and is used as a verb for running the command
Linux diff 命令 - 菜鸟教程 diff 以逐行的方式，比较文本文件的异同处。 如果指定要比较目录，则 diff 会比较目录中相同文件名的文件，但不会比较其中子目录。