What i'm trying to achieve is to combine those two variables so the output would look like a proper name. If i'm running 'tr' on it's own the result is really messy, looks like a single letter substituion:
And the reason for truncating, is to bring both Var's to equal lenght.
:confused: some one please tell me where i can possibly find out what is unix 10.2 and the basic system functions of it is. I really need help! (1 Reply)
I come across an entry in cron which is in such:
0 * * * *
What is the first 0 indicating? 0 minute? meaning a script cron as such will run every minute? :confused: (2 Replies)
Hi,
I was trying to learn forking in C in UNIX. Somehow i still haven't been able to get the concept well. I mean, i do understand that fork creates an exact replica of the parent (other than the fact that parent gets the process id of the child and child gets 0 when fork is called). This is the... (2 Replies)
Hell Unix.com Community:
I am working on a personal project using yad v0.12.4 (zenity fork) and have hit a wall on how to show a progress bar while my function is processing.
I have been all over the ABS Guide, googled 21 Linux-specific sites that I revere. I even asked on the yad-common... (4 Replies)
Hi friends,
This is a small program built on the concept of shared memory. The producer is a separate program and process, and the consumer is a seperate program and process. Both are executed under the same user account. The producer takes some string from the user and adds that string to the... (1 Reply)
I don't even know where to start with this one. There is so much out there about different aspects of this. I am starting with a basic Ubuntu 11.04 install. Do I need to configure a DNS? I am a little confused about that. What do I need to do for a domain name? I have followed various tutorials,... (1 Reply)
Hello All,
I have a problem in counting number of process getting run with my current script name..
Here it is
ps -ef | grep $0 | grep -v grep
This display just one line with the PID, PPID and other details when i print it in the script.
But when I want to count the numbers in my... (11 Replies)
hi
i am new to shell scripting.
i was going thru the part option and arguments. on this section i fail to understand the use of exit 0 in below example .
#!/bin/sh
USAGE="Usage: $0 "
case "$1" in
-t) TARGS="-tvf $2" ;;
-c) TARGS="-cvf $2.tar $2" ;;
*) echo "$USAGE"
exit 0
;;
esac... (13 Replies)
Hi folks,
If a declare a direct hash , then the hash element works fine.
my %test = ("test",1);
print %test;
print "\n";
Here in the above, the name of the hash is predeclared...
Suppose now I need to create the hash elements dynamically in the for loop.
$test="hash";
my... (1 Reply)
Discussion started by: scriptscript
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)