I moved a file with
mv file.sh /~
So I moved the file from the current directory to /~. However I have not idea what/where /~ is.
~ has a special meaning only at the start of a word. Therefore, /~ is a file named ~ located in the topmost root directory.
Normal user shouldn't be able to create files in the / directory. Be double careful when running with admin privileges and don't run commands you don't understand.