I just don't understand the difference between the two, when i use both. they "appear" to do the same thing. like what is the point of using "+" or "-" when "=" does the same thing, if i'm getting at this right.
i want:
user: to read,write, and execute.
group: to read and execute.
other: to only read.
Can anyone help explain the "s" in the below permissions example. I was reading about the "sticky bit" (t) but I am a little confused.
On file "test"
wolf% chmod 4777 test
wolf% ls -l
total 4
drwx------ 2 john staff 512 Mar 19 21:34 nsmail
-rwsrwxrwx 1 john staff ... (2 Replies)
Hi everyone, I'm looking for some information concerning Unix permissions. I am new to Unix and am doing research for a graduate class. Given the permissions below, can anyone give me five unique exploits that would be available to a hacker/cracker given this configuaration?
-rw-rw-rw- 1... (1 Reply)
I saved a perl code in xemacs. I used an xterminal to execute it but unix said that I don't have permission. I saved the files in my home directory. How do I change the permission. This is hat unix said:
-ksh: ./names.pl: cannot execute (5 Replies)
Hey,
We've got quite a strange problem on our hands here. We are running an HP 9000/800 B.11.00.
I've just created a new group in /etc/group which i called, let's say newgroup . Then I added 4 users to the group, namely user1, user2, user3, user4 . The command grpchk shows no strange things... (4 Replies)
Hi,
I am a Unix Admin. I have to give the permissions to a user for creating new file in a directory in HP-Ux 11.11 system since he cannot able to create a new file in the directory.
Thanks in advance.
Mike (3 Replies)
My /tmp is set with the following permissions (777) and a 't' at the end.
My umask is set to 022.
When I create a directory under /tmp (tmp/xx) it gets created as 755
as expected.
Yet when I create a file within that directory (/tmp/xx/yy) the permissions
are not 755 they are 644.
... (1 Reply)
Hi, I am creating a ksh script to search for a string of text inside files within a directory tree. Some of these file are going to be read/execute only. I know to use chmod to change the permissions of the file, but I want to preserve the original permissions after writing to the file. How can I... (3 Replies)
Hi,
I have noticed that on my Linux box there is a nice feature which make it impossible for specified member (owner, group or other) to have an given access if a member from which we would expect it more don't have that access.
So it is impossible to read file by all if others have set read... (3 Replies)
Hi guys,
i write the below script to make the user get to the directory that interesting. Now what I am trying is to check the permissions of the directory and if the directory exists to check the reading options.
echo "Please enter your desire folder directory ( \yourfolders) ?: \c"
... (9 Replies)
Discussion started by: mikerousse
9 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)