If you're closing stderr, and then fprintf'ing to stderr, you won't get any output.
Wow.Learned something new thanks dude.I am learning fd.I have another little question:
The following code use dup() to duplicate fd but my fd1=3, when I did fd2=dup(fd1) then why fd2 is not 3. My output shows fd2=4:
Hi there,
I found the following script on the net, i like to use it as a standard template for new scripts.
But i do not understand the meaning of the last line, can anybody explain what going on on the last line
vflag=off
filename=
while getopts vf: opt
do
case "$opt" in
v)... (9 Replies)
Hi, i've got the following:
a=`echo $b | grep '^.*/'`
i'm storing in the variable the value of the variable b only if it has a / somewhere.
It works, but i don't want to print the value. How do i give the value of b to the grep command without the echo?
thanks! (5 Replies)
Hello..
I am doing some awk-ing and among all I use substr inside it..
I have: ....substr($0,60,37)
meaning as U all know take from 37 char. from point 60..
can I put it like this substr($0,60,end of line)
meaning take it from point 60 and take all characketrs in that line until line... (2 Replies)
First af all hi.
i want to create a batch script which inform when users log in last time on system or if they are online when they logged in.
I want ot use a file .users which has the usernames of users.
i want to print for example
peter is ONLINE: Logged in on Wed Feb 11 07:47
alex... (2 Replies)
I am looking for some model like this:
My Computer
-------------
Intermediate Server (IS)
-------------
Own Server
I must be able to ssh into the Intermediate Internet Server which is generally an online version of SSH service through which I will connect to Own Server. I was the IS to... (2 Replies)
Hello All,
Im opening a file desciptor in perl and sending data using print CMD "$xyz".
is there a limit to the length of the string that I can give to this CMD at a time. (3 Replies)
Hello experts,
I am using fork() in my code but I am confused which output comes first child or parent?
I did the following code .My book shows parent first but my linux shows child first.Can anyone tell me why?
#include <stdio.h>
int main(){
int pid;
printf("I am original process with pid... (5 Replies)
I have this small program that runs with the flat assembler. My problem is that at the receive line function it receives the line and if there isn't a $ typed at the end of the user input the program displays a lot of strange stuff, sometimes beeps and then it seems to terminate without causing any... (13 Replies)
For the command below, I need to understand what exactly the command does and provide an examples for which the output will be saved to file save2... From my understanding, if the file provides an error in the first half of the pipe, it'll save to save1 and will never give an error to save to... (2 Replies)
Discussion started by: ayz649
2 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)