Hi all this is a UNIX question.
I have a large flat file with millions of records.
col1|col2|col3
1|a|b
2|c|d
3|e|f
3|g|h
footer****
I am supposed to calculate the sum of col1 1+2+3+3=9, count of col1 1,2,3,3=4, and distinct count of col1 1,2,3=c3
I would like it if you avoid... (4 Replies)
Hello All,
I have come across a small problem. It would be great if any of you could help me in resolving the issue.
one file named dummy.txt will be ftped to Unix machine twice daily. If i receive it second time in a day i need to do some processing with the file.
How to find the... (2 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
Shell script to find sum of first n numbers of Fibonacci series
2. Relevant commands, code, scripts,... (0 Replies)
I want to count the number of lines, I need this result be a number, and sum the last numeric column, I had done to make this one at time, but I need to make this for a crontab, so, it has to be an script, here is my lines:
It counts the number of lines:
egrep -i String file_name_201611* |... (5 Replies)
Hi,
Sure it's an easy one, but it drives me insane.
input ("|" separated):
1|A,B,C,A
2|A,D,D
3|A,B,B
I would like to count the occurence of each capital letters in $2 across the entire file, knowing that duplicates in each record count as 1.
I am trying to get this output... (5 Replies)
I have a file abc.csv, from which I need column 24(PurchaseOrder_TotalCost) to get the sum_of_amounts with date and row count into another file say output.csv
abc.csv-
UTF-8,,,,,,,,,,,,,,,,,,,,,,,,,
... (6 Replies)
Optimization shell/awk script to aggregate (sum) for all the columns of Huge data file
File delimiter "|"
Need to have Sum of all columns, with column number : aggregation (summation) for each column
File not having the header
Like below -
Column 1 "Total
Column 2 : "Total
...
...... (2 Replies)
1. The problem statement, all variables and given/known data:
Write a shell script that finds and display the sum of even positive integers from 0 to 100. Use the while control structure. Show your script and a sample run.
2. Relevant commands, code, scripts, algorithms:
Must us a while... (8 Replies)
Hello,
I would like to write script to tail a file for different environment
But the number of lines are keep changing
How can I write a script
For example:
env could : A, B or C
and log files could be a.log, b.log and c.log
with the number of lines can change
say sometimes it 100 last... (9 Replies)
Discussion started by: encrypt_decrypt
9 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)