When I was still a student, I accidentally erased all my project source code with: rm * .o I was puzzled by the message ".o: No such file", and then understoo

When I was still a student, I accidentally erased all my project source code with: rm * .o I was puzzled by the message ".o: No such file", and then understood why... Now, I always start with ls and if satisfied of the output, replace ls with rm