Karlis Abele | Printful wrote: > *How to reproduce:* Thank you for the simple test case.
> Create an archive like so *tar -zcf test.tar.gz .* At that point there are two problems of usage. 1. Creating the output file in the same directory that is getting archived This is not a good practice. It creates a situation where the order of actions matters. For example if one decided to do this twice then test.tar.gz will get included into the archive that is being created in test.tar.gz which can have bad effects. Of course the first time around it all depends upon if tar reads the input directory before or after creating the output file. Best to avoid it and put the output archive into a different directory. 2. Creating an archive of "." This is not a good practice.It is rarely done. Usually if one is going to archive up files in a directory they would archive ./* so as to match the files. Of course one needs to know that * does not match hidden files (files that start with a dot) and usually that is the right thing to do. And that it will recursively archive all directories that matched too. > And extract it somewhere *tar -zxf test.tar.gz -C /var* > Now the /var ownership is *1234:1234* As expected because "." was 1234:1234 in your input and it was copied to the output. It is doing exactly what it has been told to do. This is exactly the same as if one were to have copied dot there "cp -a . /var". It's the same thing. And the same reason why it is against good practice. Have you ever accidentally cut yourself with a kitchen knife? Of course everyone who cooks has at one time or another cut themselves with the kitchen knife. Kitchen knives are dangerous. Kitchen knives are sharp. Therefore we must remove all knives from the kitchen and ban their use there. Now go cook! Obviously that will now be very difficult. And therefore instead we learn how to use kitchen knives with skill. > This means that if for example I extract the archive that is created in a > similar manner to for example /root, it will mess up the root directory > ownership (possibly) and can pretty much brick the instance Yes. Don't do that. > I understand that there are flags regarding ownership and permissions when > extracting archives, but I do think that using the . should not make it so > that after extracting the archive it changes ownership of the target > directory But that is exactly what it should do since that is exactly what it was told to do. The solution is not to tell it to do it. Sometimes people watch Hollywood movies and think we have arrived at a point in time where programs can be artificially intelligent enough to know when we are doing something bad and could then warn us of this bad thing. Perhaps they could become a guardian to us preventing us from ever getting hurt. Maybe one day that dream will be realized but as of yet that is simply not possible. It is impossible to have a kitchen that works without having a kitchen knife in it and it is impossible for the program to know when something it has been instructed to do is bad too. Instead we must use our kitchen knives with care when cooking in the kitchen. Bob
