I have to solve a problem for my wife who is engaged in Research in Breast Cancer.
1. She has frequently to search a long single line of alphabetic characters (lower case) for an exact match of a string.
e.g.... (1 Reply)
How do I Ftp, and rename multiple files in one unix script. I have to send it with .tmp extension , then rename it to .txt after FTP is done . I need to do a Mass rename of more than 1 file in a shell script , Urgent help required. (1 Reply)
I have two files file1 and file2 as shown below:
file1:
name
nameabc
bcd
nameabcdefg
file2:
age
age1111
age2345
age6743
I have pasted one file on the other with the delimiter "|" and the resulttant file is:
name|age
nameabc|age1111
bcd|age2345
nameabcdefg|age6743 (6 Replies)
Hi,
i want to write a script that executes a program (exec?) .
this program then requires a filename as input.
how do i give it this input in the script so the program will be complete run and close by the script.
e.g.
exec prog.exe
program then asks for filename
"enter filename:"... (1 Reply)
My data is something like shown below.
date1 date2 aaa bbbb ccccc
date3 date4 dddd eeeeeee ffffffffff ggggg hh
I want the output like this
date1date2 aaa eeeeee
I serached in the forum but didn't find the exact matching solution. Please help. (7 Replies)
The circumfrence of a circle is
#!/usr/bin/perl
print 2 * 3.141592654 * 12.50 \n"; # pi= 3.141592654
# r= 12.50
I need a simple program showing me all the steps..to modify the above to prompt for and accept a radius from the person running the... (3 Replies)
I know it looks like a stupid question, but i really wanna know the reason.
Actually, i think it's because the c compiler will detect it as the end of file "EOF" of the program, but, am i wrong? because it compiles it anyway, but keep showing warnings like "no new line at the end of file".
I... (8 Replies)
I wrote a simple program that generates a random word 10,000,000 times.
I wrote it in python, then in C++ and compared the two completion times. The python script was faster! Is that normal? Why would the python script be faster? I was under the impression that C++ was faster. What are some of... (2 Replies)
Long story short: I'm working inside of a Unix SSH under a bash shell. I have to code a C program that generates a random number. Then I have to call the compiled C program with a Perl program to run the C program 20 times and put all the generated random #s into a text file, then print that text... (1 Reply)
I created a program, so a kid can practice there math on it. It dispenses varies math problems and the kid must input an answer. I also want it to grade the work they have done, but I can't find the best place for it to print out the grade.
I have:
if ( $response =~ m/^/ ) {
$user_wants_to_quit... (1 Reply)
Discussion started by: germany1517
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)