Hi,
How can i delete the second and subsequent occurrence of a particular string from a file ?
eg) test.txt
cattle
bat
battle
mat
matter
cattle
cattle
my output file should be
cattle
bat
battle
mat
matter (12 Replies)
I am looking to replace two or more strings on different lines using sed, but not with the same variable. IE
# cat xxx.file
<abc>
abc def ghi
abc def ghi
abc def ghi
currently I can only change each line with the same pattern:
# sed -e '/<abc>/!s/abc\(.*\)/jkl mno/' xxx.file
abc jkl mno... (3 Replies)
Hello Experts,
I have two files called "old" and "new". My old file contains 10 lines and my new file contains 10 + "n" lines.
The first field in both these files contain ID. I sort these two files on ID. I am interested in only the lines that are in the new file and not in old.
I tried... (4 Replies)
I have an input text that looks like this (comes already sorted):
on Caturday 22 at 10:15, some event
on Caturday 22 at 10:15, some other event
on Caturday 22 at 21:30, even more events
on Funday 23 at 11:00, yet another event
I need to delete all the matching words between the lines, from... (2 Replies)
Hello,
Merry Christmas to all! I wish you the best for these holidays and the best for the next year 2011.
I'd like your help please, I need to delete all the rows in the third column of my file, but without touching nor changing the first and last value position, this is an example of my... (2 Replies)
Hi. I'm hoping that someone can help me with a bash script to delete a block of lines from a file.
What I want to do is delete every line between two stings that are the same,
including the line the first string is on but not the second.
(Marked lines to match with !)
For example if I... (2 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)
I am trying to extract a table of data (mysql query output) from a log file. I need to print everything below the header and not past the end of the table. I have spent many hours searching with little progress. I am matching the regexp +-\{99\} with no problem. I just can't figure out how to print... (5 Replies)
If we want to display lines from file leaving last 30 lines. i dont know the count of lines in file (14 Replies)
Discussion started by: mirwasim
14 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)
08-18-2016
