First problem, strange file name: "~" is a joker character in AmigaDOS. It must not be used in file names. You cannot delete the file because you cannot enter the "~" as a part of the file name, it is always interpreted as a joker by the delete command. You have to use another joker to replace it.
Not exactly correct. You can use ' character in front of joker character to "neutralize" it. I.e. command delete '~backdrop should delete file ~backdrop.
If you have a file "?" you can delete it with command delete '? etc etc.
