Hello,
With the following small script I list the size of documents belonging to a certain user by each time selecting the bytes-field of that file ($7). Now it fills the array with every file it finds so in the end the output of some users contains up to 200.000 numbers. So how can I calculate... (7 Replies)
awk '
FILENAME == "all" { balance += substr($0,17,13)
dt = substr($0,6,8) }
END { for ( name in balance )
printf("%013s %3s of %8s\n", balance/100,name,dt) | "sort "
} ' all > summation
using this code i wanted to take summary totals of... (3 Replies)
Hello,
I have written a script in a previous server and its being migrated to a new server. I'm trying to debug my script since i've had to make minor changes to it to get it to work.
I'm having a hard time getting my totals to populate
here is the syntax
DUMP_COUNT=`sqlplus -S... (4 Replies)
Afternoon,
I have a script which creates/modifies data into a formatted csv.
The trailer record should display 2 columns, the first is a static entry of "T" to identify it as a trailer record. The 2nd is a total of amounts in a column throughout the entire file.
My total isn't displaying... (8 Replies)
Chess game. Has anyone installed and run Fritz Grand Master Challenge chess on Ubuntu 11.10/ Unix? I have read about disappointments with different versions of wine, but not successes. (0 Replies)
Hi,
I have a similar input format-
A_1 2
B_0 4
A_1 1
B_2 5
A_4 1
and looking to print in this output format with headers. can you suggest in awk?awk because i am doing some pattern matching from parent file to print column 1 of my input using awk already.Thanks!
letter number_of_letters... (5 Replies)
Hello all,
I have a very basic question. I have a requirement where in, I have a main process which forks a child process, which execs and runs a c executable corresponding to a daemon. In the c executable corresponding to a daemon, as everyone does, I fork another child process, and as part of... (7 Replies)
Discussion started by: sai2krishna
7 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)