Hi all,
I've got the problem which I can't resolve with my knowledge :)
For xterm terminal we have resource class XTerm*backarrowKey. If we set it to true, backspace code (ASCII 0x8) will be sent to program. We can get it using e.g. getc() function. If it is disabled getc() returns DEL(0x7F). ... (0 Replies)
Hi all,
I have been using Ubuntu for 2 years now, and a few days ago I bought a Macbook. This is my first time using a Mac, so I have spent the better of two days learning the user interface, and configuring my Macbook. One thing I noticed is that there is no easy way to turn on and off hidden... (0 Replies)
Hi,
I need help to toggle through dates on a weekly basis to be fed into a script as inputs. The format should be: yyyy/mm/dd (start) yyyy/mm/dd (end), where end date is 7 days increments.
The date (start) would be input as an ARGV and would continue until current date.
I can check... (2 Replies)
hi all
is possible to pass shell (bash) variable to sed like it is in awk?
example:
awk script is storred in awk.awk file and I am passing variable called var to this file.
$ cat awk.awk
{if ($5==var) print $0}
so it works when i issue
$ bash_var=24
$ ls -l | awk -v... (1 Reply)
I remember there is a sed switch i can use to edit and save the file at the same time, but i cannot recall it at all.
so instead of
-> sed 's/A/B/' file > file-tmp
-> mv file-tmp file
what can i do to just let sed edit and save the "file" (4 Replies)
Hi Guys,
i'm exploring sed and failed to understand the following. Can anyone with more knowledge of this explain this better.
I have to read lines 4 to 6 in a file so i used the following command :
sed '4,6 p' file
but the above prints all lines instead! . when i use the -n... (3 Replies)
I have checked the man page ,which says :
The -H (HOME) option sets the HOME environment variable to the homedir of
the target user (root by default) as specified in passwd(5). By default,
sudo does not modify HOME
But I have tried below command:
#... (1 Reply)
I have an input file that looks something like this:
....
key1: ABC
....
key2: DEF
....
key1: GGG
....
key2: HHH
....
The row of dots represents any number of lines that don't contain the strings "key1:" or "key2:" The strings key1: and key2: will always appear alternately as in the... (8 Replies)
Discussion started by: pmennen
8 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)