Hi All,
I am new to this shell scripting world. Struck up with a problem, can anyone of you please pull me out of this.
Requirement : Need to get the index of a substring from a parent string
Eg : index("Sandy","dy") should return 4 or 3.
My Approach :
I used Awk function index to... (2 Replies)
hi,
im quite new to perl regexp. i have a problem where i want to extract a word from a given string. but the word is unknown, only fact is that it appears as the second word in the string.
Eg.
input string(s) :
char var1 = 'A';
int var2 = 10;
char *ptr;
and what i want to do is... (3 Replies)
i have srtring i.e. "NAME,CLASS,AGE" (length of string is not constant) and from this string i've extract each word delimited by "," (comma).
INPUT: "NAME,CLASS,AGE"
OUTPUT: NAME
CLASS
AGE
how can i do that?
i have tried some string manipulation function like... (5 Replies)
Hi,
I'm a newbie to shell scripting and have searched the forum but couldn't find what i was looking for.
Basically I have a list of filenames like...
123-fileone.txt
I want to be able to extract the prefix up to the first '-'. So I'd end up with 123. I have attempted it using a pretty... (2 Replies)
I’m looking for an elegant way to convert a delimited file (comma delimited in this case) to padded columns (for printing in non-proportional font) but the length of each column is not known ahead of time. It needs to be calculated for each column from the longest entry in that column in a given... (3 Replies)
Hi,
I have an input string say for example:
ABC,DEF,IJK,LMN,...,XYZ
The above string is comma delimited. Now I have to extract the last part after the comma i.e. XYZ.
:b: (3 Replies)
Hi
I have a file which contains wrong XML, There are some garbage characters at the end of line that I want to get rid of. Example:
<request type="product" ><attributes><pair><name>q</name><value><!]></value></pair><pair><name>start</name><value>1</value></pair></attributes></request>�J ... (7 Replies)
Hi gurus,
I am trying to figure out how to extract substring from file line (all lines in file), as specified position and specified legth.
Example input (file lines)
dhaskjdsa dsadhkjsa dhsakjdsad hsadkjh
dsahjdksahdsad sahkjd sahdkjsahd sajkdh adhjsak
I want to extract substring on... (5 Replies)
I realize this general issue (inputting strings of variable length in C) has been addressed in myriad locations before, but I'm interested in knowing why my specific approach is not working. (BTW I'm intentionally keeping the size increments small so that I can more easily follow what's going on.... (5 Replies)
Discussion started by: DevuanFan
5 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)