DEL deletes a file. There is no bin and no undo here: MS-DOS came from a time when the computer assumed you meant what you said. Read the name twice before pressing Enter.

Now put the last two lessons together in your head. A wildcard makes DEL far more dangerous than it looks: DEL *.TXT would take every text file in the folder without asking, and DEL *.* would empty it completely. Both of those were typed by mistake a great many times.

DIR *.TXT afterwards: the file is not in the list any more, and there is nowhere to go looking for it.