what am trying to do is delete a line in a specific file but I dont know what to do. I cant use the sed or awk commands because these commands dont really alter the original file. they only alter what they display on the screen
by the way, am trying to do this from a script so if anybody can... (5 Replies)
I have a file which has about 500K records and I need to delete about 50 records from the file. I know line numbers and am using
sed '13456,13457,......d' filename > new file.
It does not seem to be working.
Any help will greatly appreciated. (5 Replies)
Input:
a
b
b
c
d
d
I need:
a
c
I know how to get this (the lines that have duplicates) :
b
d
sort file | uniq -d
But i need opossite of this. I have searched the forum and other places as well, but have found solution for everything except this variant of the problem. (3 Replies)
Hi All,
I have a very huge file (4GB) which has duplicate lines. I want to delete duplicate lines leaving unique lines. Sort, uniq, awk '!x++' are not working as its running out of buffer space.
I dont know if this works : I want to read each line of the File in a For Loop, and want to... (16 Replies)
Hello,
I have file of more than 10000 lines.
I want to delete 40 lines after every 20 lines.
e.g from a huge file, i want to delete line no from 34 - 74, then 94 - 134 etc and so on.
Please let me know how i can do it.
Best regards, (11 Replies)
Hi,
I have a txt document having a format like this:
DATA1 | DATA2 | DATA3 | 23-JAN-20 23:41:34
DATA1 | DATA2 | DATA3 | 23-JAN-20 23:41:32
DATA1 | DATA2 | DATA3 | 23-JAN-20 23:41:30
...
DATA1 | DATA2 | DATA3 | 23-JAN-20 22:35:31
DATA1 | DATA2 | DATA3 | 23-JAN-20 22:30:34
DATA1 | DATA2 |... (1 Reply)
Discussion started by: gc_sw
1 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)