It's quite possible to have files belonging to users or groups with no corresponding entry in /etc/passwd or /etc/group, nothing prevents it. Anything with sufficient privileges can create files belonging to any ID and group whether represented by anything in passwd or group or not; those only control login permissions through the traditional login system.
All users and groups are just numbers anyway. If ls doesn't find matching entries in passwd and/or group it will just display numbers. As long as whatever login manager involved sets correct access permissions on login based on the relevant user and group numbers, and the numbers used internally and externally don't overlap, things can be kept consistent without knowing all names locally.
Last edited by Corona688; 05-27-2010 at 12:17 PM..
im running into changing the ownership of a file. I am trying to change the ownership to "system", but it doesn't want to work. I
sudo chown system /preferences.plist
Password:
chown: system: Invalid argument
is there a way to read the ownership of a file, something like
read chown... (3 Replies)
Hi Folks,
I know that changing users and groups is pretty basic admin, but this one has got me stumped. When I try to change the group of a file for which I am the owner for, it still gives me a 'Not owner' error.
For example, when I am logged in as 'webadmin', I have the following file:
... (4 Replies)
Hello,
I am on a mission to determine the user of file. I have used the ls -l command but it displays permission, link, user, group, etc, but I just want to display just the name of user of a specified file.
Many thanks (4 Replies)
hi,
how can I get the owner of the file ( not uid) on windows plaform.
"getpwuid" is not working on windows. I knw it works on unix.
Thanks. (2 Replies)
Hi all,
We have some files are under 744 permissions and the the owner is say owner1 and group1.
Now we have another user owner2 of group2, owner2 can remove files of the owner1 and the permission of those files are 744, unix admin told us he did some config at his side so we can do that.
... (14 Replies)
What i did:
- logged in with acc1 and created a new user acc2
commands used: useradd and passwd.
- Then i logged in acc2. but all the files are owned by acc1.
Issue: I try to change the owner of the files using chown command . But it gives me a error message.
All i want to do is... (13 Replies)
i need to do the following operations in solaris 10:
1.change owner and group owner for files which are not owned by the current user and user group
2.to can delete files in the /tmp directory which are not of the current user
3. allow to a standard user the deletion of files in the /tmp... (1 Reply)
hi everyone,
We've generated mpstat.out file monitoring cpu utilization and the file is ready now.Wanted to generate graphical charts for the same output data.
Can anyone pleas suggest tool for the same.? (1 Reply)
Discussion started by: Kathraji
1 Replies
LEARN ABOUT DEBIAN
bup-margin
bup-margin(1) General Commands Manual bup-margin(1)NAME
bup-margin - figure out your deduplication safety margin
SYNOPSIS
bup margin [options...]
DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two
entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids.
For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit
hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by
its first 46 bits.
The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits,
that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits
with far fewer objects.
If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if
you're getting dangerously close to 160 bits.
OPTIONS --predict
Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer
from the guess. This is potentially useful for tuning an interpolation search algorithm.
--ignore-midx
don't use .midx files, use only .idx files. This is only really useful when used with --predict.
EXAMPLE
$ bup margin
Reading indexes: 100.00% (1612581/1612581), done.
40
40 matching prefix bits
1.94 bits per doubling
120 bits (61.86 doublings) remaining
4.19338e+18 times larger is possible
Everyone on earth could have 625878182 data sets
like yours, all in one repository, and we would
expect 1 object collision.
$ bup margin --predict
PackIdxList: using 1 index.
Reading indexes: 100.00% (1612581/1612581), done.
915 of 1612581 (0.057%)
SEE ALSO bup-midx(1), bup-save(1)BUP
Part of the bup(1) suite.
AUTHORS
Avery Pennarun <apenwarr@gmail.com>.
Bup unknown-bup-margin(1)