I am writing a c++ program that has many calls of pow(input,2). I now realize that this is slowing down the program and these all should be input * input for greater speed.
There should be a simple way of doing this replacement throughout my file with awk, but I am not very familiar with awk.... (2 Replies)
Hi,
I have a file having around 30 records. Each record has 5 fields delimited by PIPE. Few records in the file having Junk characters in the field2 and field4.
I found the junk charcter and I tested it and replace the junk with space with the command below
perl -i -p -e "s/\x00/ /g"... (1 Reply)
Hello, I am using awk to match text in a tab separated field and am able to do so when matching the exact word. My problem is that I would like to match any sequence of text in the tab-separated field without having to match it all. Any help will be appreciated. Please see the code below.
awk... (3 Replies)
Dear All,
I have file with 4 columns:
1 AA 0 21
2 BB 0 31
3 AA 0 21
4 CC 0 41
I would like to find the duplicate record based on column 2 and replace the 4th column of the duplicate by a new value. So, the output will be:
1 AA 0 21
2 BB 0 31
3 AA 0 -21
4 CC 0 41
Any suggestions... (3 Replies)
I have 2 files A.txt and B.txt
A.txt 3 fields and separate by a comma
some,thing,florida
any1,thing1,california
some2,thing2,dallas
just,fun,kansas
B.txt has 8 fields and separate by a comma
what,ever,florida-state,,,,,,
some,one,dallas_state,,,,,,
You will see 3rd fields are the... (5 Replies)
Hello,
I'm trying the solve the following problem.
I have a file which I intend to use as a csv called master.csv
The columns are separated by commas.
I want to change the text on a specific row in either column 3,4,5 or 6 from xxx to yyy depending upon if column 1 matches a specified pattern.... (3 Replies)
Hi,
I have an input file with below data and rules file to apply search and replace by each field in the input based on exact value or pattern.
Could you please help me with unix script to read input file and rules file and then create the output and reject files based on the rules file.
Input... (13 Replies)
Hi there,
First of all this is my first post here. Thank you in advance for your help.
What I am trying to do is the following. I have a text file where each field of each row is separated by a tabulator.
Looks like this:
ATOM 1 N HSE A 26 3.033 -10.429 -2.262 1.00 17.07 ... (8 Replies)
Hello friends,
I have huge file with many sets where each "set" has few lines and each set always begins with "Set" in Sq brackets as shown above.
# cat file1 (2 Replies)
Hi All,
Seeking for your assistance on how to search and replace the last field/column. please see sample below:
inputfile1.csv
="8923523434",="543623534"="afd23535623",="100"="200"
="8923523431",="543623536"="afd23535626",="101"="201"... (3 Replies)
Discussion started by: poginiks
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)