I am using grep to find header info in a file and print it to another file. The header info only shows up on line 3 and 4 so i really don't need to search the remainder of the file. the grep -m option doesn't work with my version of UNIX. Also I'm new to UNIX so could you please explain what... (4 Replies)
Hi, I've been trying to figure this one out and found a post about this on the forum here but the solution didn't seem to work for me. Basically what I have is a file that looks something like:
stuff
morestuff
0
otherthing
0
etc
I want to substitute for the 0 but what I want to... (9 Replies)
hi
i have one file where i want to substitute only first instance of
swap
with swap1
i want to replcae only first instance of swap in my script
i know we can do this with awk. but i need to do this with sed only
i tried follwoing code
sed 's/swap/swap1' filename
but here all... (15 Replies)
Hi,
Here is my piece of code used with sed in shell script:
sed -i '/<falsemodule-option>/ a\<LdapLogin>' myxmlfile
The problem that i am facing with the above is that in 'myxml' file i have mulitple instances of <falsemodule-option>
so when i execute the above sed command, it is appending... (10 Replies)
I need to reduce a file's size below 50MB by deleting chucks of text. The following sed does this.
sed '/^begpattern/,/endpattern/d' myfile
However, it's possible that the file size can get below 50MB by just deleting the first instance of the pattern. How do I code that into sed?
Or can awk... (8 Replies)
I was told a way to do this with awk earlier today but is there a way with sed to specify the last instance of a character on a line?
You will know what character you're looking for but there could be none or one hundred instances of it on a line say and you ONLY want to specify the last one for... (3 Replies)
The following text is in testFile.txt:
one 5
two 10
three 15
four 20
five 25
six 10
seven 35
eight 10
nine 45
ten 50
I'd like to use sed to print the first occurance of search pattern /10/ in a given range. This command is to be run against large log files, so to optimize efficiency,... (9 Replies)
Hi all,
I'm new to the forum and also relatively new to sed and other such wonderfully epic tools.
I'm attempting to grab a section of text between two words, but it seems to match all instances of the range instead of stopping at just the first.
This occurs when I use:
sed -n... (7 Replies)
The intended result should be :
PDF converters
'empty line'
gpdftext and pdftotext?xml version="1.0"?>
xml:space="preserve"><note-content version="0.1" xmlns:/tomboy/link" xmlns:size="http://beatniksoftware.com/tomboy/size">PDF converters
gpdftext and pdftotext</note-content>... (9 Replies)
Discussion started by: Klasform
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)