08-15-2007
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
How can I set the value for IFS variable (2 Replies)
Discussion started by: mahabunta
2 Replies
2. Shell Programming and Scripting
hi, :)
I set IFS=":"
But when i try to echo $IFS,i am not getting any thing on the screen escept a blank line.
any help pls.
cheers
RRK (11 Replies)
Discussion started by: ravi raj kumar
11 Replies
3. UNIX for Dummies Questions & Answers
Hi!
I am working in korn shell. I want to reset the dimiliter for the set command to "|" but instead of a command prompt return I am getting something as below
After issuing the command I am getting this....as if the shell is expecting something else. Can anybody suggest what's the problem.
... (2 Replies)
Discussion started by: udiptya
2 Replies
4. Shell Programming and Scripting
Hi can someone tell me whats wrong with the following:
#!/bin/sh
file1=$1
file2=$2
if
then
if
then
echo "File 1 is" $file1
echo "File 2 is" $file2
cp $file1 $file2
echo "Copy complete!"
else
echo "ERROR: File does not exist!"
... (8 Replies)
Discussion started by: philmetz
8 Replies
5. Shell Programming and Scripting
hi i am a learner
can some explain "export IFS=$(echo "\n\t\a")"
i am not able to understand the functionality
please help
thanks
Satya (1 Reply)
Discussion started by: Satyak
1 Replies
6. Shell Programming and Scripting
im messing up somehwere...and can't seem to clean up the script...for it to work
objectives:
1. check for today's file, and sleep 30 secs between retries
2. only allow 5 tries before script should fail.
3. if today's file found, wait 30 seconds for it to process..
code:
count=0... (8 Replies)
Discussion started by: sigh2010
8 Replies
7. Shell Programming and Scripting
Hi,
This is out of curiosity:
I wanted to extract year, month and date from a variable, and thought that combining read and IFS would help, but this doesn't work:
echo "2010 10 12" | read y m d
I could extract the parts of the date when separated by a -, and setting IFS in a subshell:
... (3 Replies)
Discussion started by: raphinou
3 Replies
8. Shell Programming and Scripting
Given the scenario like this, if at all if have to use IFS on the below given example, how it should be used.
IFS=/
eg:
/xyz/123/348/file1
I want to use the last slash /file1 . So can anyone, suggest me how to pick the last "/" as a IFS. (4 Replies)
Discussion started by: raghunsi
4 Replies
9. UNIX for Dummies Questions & Answers
how to use nested ifs in unix (1 Reply)
Discussion started by: pratima.kumari
1 Replies
10. Shell Programming and Scripting
hi I keep getting an error with this nested if statement and am getting the error unexpected end of file, can anyone help me as to why this wont execute?
#!/bin/bash
#script to check wether the -i -v statements run correctly
removeFile ()
{
mv $1 $HOME/deleted
}... (3 Replies)
Discussion started by: somersetdan
3 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)