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don.joey
Asked: 2017-01-26 05:20:58 +0800 CST

How to set permissions so that files cannot be deleted?

  • 772

Is there a way to setup a directory such that files and directories

  • can be read
  • written to
  • created

but NOT deleted. This is for my photo archive. I want to avoid accidentally deleting photos. Is there a way to do this?

PS/ I have set the archive up using bindfs if that is any help. Two users and one group have 0750 access.

permissions

1 Answers

  1. You can set the append-only attribute. From man chattr:

    A  file  with the `a' attribute set can only be open in append mode for
writing.   Only   the   superuser   or   a   process   possessing   the
CAP_LINUX_IMMUTABLE capability can set or clear this attribute.

    For directories, this means that new entries can be created, but no entry can be renamed or deleted:

    $ mkdir foo
$ sudo chattr +a foo
$ touch foo/bar
$ echo a > foo/bar
$ rm foo/bar
rm: cannot remove 'foo/bar': Operation not permitted
$ mv foo/bar foo/baz
mv: cannot move 'foo/bar' to 'foo/baz': Operation not permitted

    This attribute does not inherit, so you will have to apply this to all subdirectories recursively:

    sudo find . -type d -exec chattr +a {} +
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