As usual, you can type ls to see the result of mv.

When you type ls, files beginning with a dot are not listed.

You might type ls to verify that your new directory exists.

Now type ls -l and notice that secondlink is still there.

If you're curious, cd to each directory and type ls to see its contents.

You quickly get tired of typing ls -almost-all -color=auto.

Try typing ls to verify that there's indeed a file called profile in your working directory, alongside the new mysubdirectory.