Hi,:cool:
I have a list of files in a directory.I need to store them in a file with the prefix of @ by using a command..
ex:@p_po.plb
@p_ebiz_roster_data.plb
any idea pls.
cheers
RRK (2 Replies)
Hi I have a very large csv file with some hundreds of thousands of rows of data.
The data is in the following format:
Up to four alpha numeric characters for the first word. This is either set as 2 characters followed by 2 spaces, or as a single 4character word. This is then followed by an 8... (7 Replies)
Hi,
In my shell script i have to match a patten in a file , if found i have to prefix the entair line by a "word"
eg. pattern = "aaa" prefix= #123
file: bbbb xxx
zzzz aaaa
qqqq kkkk
outPut file: bbbb xxx
... (5 Replies)
Hi all first post here.
quick question what Solaris 10 update level included this utility?
I have a bunch of Sun boxes at varying levels of Solaris 10 some have it some do not.
When I do my install I take the full option for the packages to install on all the systems.
thanks in advance... Mike (4 Replies)
Hi,
I have a Python unit test cases source code file which contains more than a hundred test case methods. In that, some of the test case methods already have prefix 'test' where as some of them do not have. Now, I need to add the string 'test' (case-sensitive) as a prefix to those of the... (5 Replies)
I need to shred and delete a file after a certain time. Therefore I use
shred -z /path/to/file.txt | rm -rf /path/to/file.txtIt works well, but typing
in that very directory
ls -shiI still see the so called backup-copy lets say file.txt~
When running bleachbit it will disappear thoroughly.... (3 Replies)
#!/usr/bin/ksh
# This script reads the *.rpt files created by xenos during job execution.
# The job name, jobid, number of pages processed and pdf files created for each job
# are added to the xenoshistory.txt file
Currently the ouput file looks like this but I need a date where the... (3 Replies)
Discussion started by: bcarosi
3 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)