Hi All,
I have used this forum many times to solve my many scripting problems. This time, I would like to seek some answers to a problem that I've been head scratching quite a bit on.
My Example:
I am converting a 2000-byte file into a 300-byte file
this file has no delimiters and hardly any... (3 Replies)
Hi All,
I have a flat file with ~ as de-limiter (e.g: aaa~ba a~caa~0~d~e)
What I want is check if the 4th character is 0 and replace it with say 4. So now it becomes : aaa~ba a~caa~4~d~e.
I have to do this for the whole file, but the delimiter position remains the same, not the... (10 Replies)
Hi
Can somebody help me with solution for this PLEASE?
I have a flat file and need to insert delimiters at fixed positions in all the lines so that I can easily convert into EXCEL with columns defined as per their width.
For Example
Here is the file
{
kkjhdhal
sdfewss
sdtereetyw... (7 Replies)
I can't seem to get sed to allow me to insert text in the first line of an empty file. I have a file.txt that is a 0 byte file. I want sed to insert " fooBar" onto the first line. I've tried a few options and nothing seems to work. They work just fine if there's text in the file tho. Help? (4 Replies)
We receive a file which usually has 40 to 50 million rows. I want to set up an audit process by which everytime we receive a file we audit it for # of rows and total number of columns.
So if the # of rows is around 1 million on a particular day, I want to raise a flag or send an email....and if... (3 Replies)
Hello Guys
Please help me with the below issue
I want to read a flat file source upto certain number of columns
Say my flat file has 30 columns but I want to read upto 25 columns only
How come the above issue can be addressed?
Thanks a lot!!!! (1 Reply)
I have an awk script to extract data from several files and create output in the following format as a csv file:
xxxx 01/04/12 0001 0
When data is present, I have a file. When no data is available in the input files, I would still like to create a file that looks like this:
xxxx... (1 Reply)
Greetings:
I generate an empty flat file just fine when there's no data returned from my process, as the customer wants one always (using the 1st line of the below script). However, they also want at least the column names in this flat file (row 1, the only row to be in the emply file). I'm... (7 Replies)
Hi All ,
I have pipe delimiter file with 11 columns . I need to insert 4 empty columns after column 10 . and After 11 column I need to insert a column which is having the same value for all the rows .
My file
1|2|3|4|5|6|7|8|9|10|11
New file
... (11 Replies)
Would like to insert value between two empty delimiter and at the very last too if empty.
$ cat customerleft.tbl
300|Customer#000000300|I0fJfo60DRqQ|7|17-165-193-5964|8084.92|\N|p fluffily among the slyly express grouches. furiously express instruct||||||||||||||||||||||||\N... (3 Replies)
Discussion started by: Mannu2525
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)