*. Really.

My first taste of Unix was a somewhat austere version of HP-UX, with basically no application beyond those shipped with the system (except for Netscape Navigator 2.0). It was my second year at university, and for the first time I had permanent access to Unix workstations. We had a brief course on "survival Unix skills" (ls, cd, cp, reading mail - with elm), and learning the rest was left as an exercise to us poor little students.

There were two text editors on these workstation. The first one was vi, but our well-intentioned teachers strongly advised us not to use this program, something along the line of "You innocent newbie, you no use vi ! bad bad bad bad !" (I can't blame them for that, some of the students had dificulties with Word).

So the only text editor we had was textedit, which was basically a clone of notepad - only uglier. We edited all our text with it, mail, C code, whatever.

Now that program had a peculiar "feature": in the "Save As" dialog box, the default name was "*". That is, if for some reason you clicked on "OK" or pressed "Enter" before specifying the filename, it was saved as "*". Someday, after writing something (I don't remember what) with that editor, I decided to save it and clicked on "Save As", but then I changed my mind and tried to "Cancel" out the dialog box. Being a mere mortal, and as such subject to failure and to Murphy's law, I clicked on the wrong button and the file was saved under the name "*".

Disk space was severely restricted (1 MB for each 1st year student), so I decided to delete this file to save some room. "How do I delete a file already ? Ah, yeah, 'rm'. Okay, here we go.."

      $ rm *
I suppose you can figure out how I felt when I realized the consequences ("what, there's no 'undelete' on that things ?")

My conclusion: Never use * as a filename, but more than this, never, ever use a program that is brain-damaged enough to save files as "*" by default. Oh, and if you can, don't use HP-UX at all. That's my conclusion.