This command has two purposes. First, it will update the last modified time on a given file. This is useful if you want to update a cache or simply make a program reload a configuration file. Second, if the file doesn’t exist, touch will create it:
You can see that initially, it created a file called test. The initial timestamp is Oct 23 05:20. A minute or so later we used touch on the file again and took another look. You can see that the timestamp now shows Oct 23 05:21.