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Thread: a quick (rm) trick: *nix

  1. #1
    Join Date
    Dec 2002

    a quick (rm) trick: *nix

    While playing around on the school's unix sys I found a neat trick
    just from playing around with the cat command.
    It is feared that a unix newbie will try a 'rm *' or a 'rm -rf *' command.
    that will deleted his whole file sys for his account.
    So I did a 'cat>-z'
    then catted -z file it was empty as I like it to be.
    then try a rm * it gave me a invalid option mesg
    then try a rm -rf * the same mesg happen again.
    it would let me excute the rm * command. For as I know I guess the
    -z file is passed or seen as part of the rm command.
    (note:try in a create directorywith garbage files in this dir)
    it will not remove none of the files with a rm * U have to use the file name.
    If anyone can tell me more about how this works I would greatly love the info.

  2. #2
    Join Date
    Dec 2002
    I guess it's because when you use * , it adds the -z to the command line
    rm -rf -z , and since it's not a valid option, it produces the error message. Since -z would be the first file to be picked, it seems to be a nice protection against mass deletion.. . All I have to say.. hope that's the explanation. If there are some more esoteric issues involved, I dunno.

  3. #3
    Senior Member problemchild's Avatar
    Join Date
    Jul 2002
    Yes, that's exactly what's happening. Any file whose name begins with a "-" will be seen as a command line option instead of a file. I discovered this a while back when I got my new HP digital camera working under Linux and realized it liked to name images -001, -002, -003, etc...
    Do what you want with the girl, but leave me alone!

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