That tests if the standard input (FD # 0) is a terminal.
If it is a terminal then a prompt can be printed if it is a pipe then no prompt is necessary. The prompt should probably be printed to stderr so that if you redirect to a file it is still visible:
I am trying to check to see if a file exists on a ftp server, well, I know that cant be done, atleast directly, So I came up with this small script
ftp -n $HOST <<END_SCRIPT
quote USER $USER
quote PASS $PASSWD
cd public_html/crap
dir $FILE
quit
END_SCRIPT
Where the $ variable... (2 Replies)
Hi List,
How to read the output of a command executed from a script.
For ex.
sample_scritp.sh
-------------
useradd testuser1
password testuser1
....
.....
--------------
This prompts for "password", and "confirm password", for which i need to give the values from script.
Can... (4 Replies)
i want to redirect output of one command as the command line argument of another script
for example, say i would run this command:
find . -xdev -type f -size +4096 -exec ls -al {} \;
i wan to be able to do something like:
echo +4096 | find . -xdev -type f -size ****** -exec... (3 Replies)
Hi ,
I would like to assign command (with pipe) output to a variable. The code is as follows. The goal of the code is to get the last folder folder with a particular name pattern.
myDate=`ls | grep 2009 | tail -1`
echo "myDate=" $myDate
However, in the presence of the pipe, the code... (3 Replies)
Hi,
I am having a list of directories with different login id's. My requirement is that i need to list the directories of my id and need to delete them. So i am using following code
ls -ltr ¦ grep userid ¦ rm -rf
But this is not working. So is there any way of doing it. Please note... (3 Replies)
xargs work great when a command gives multiple line output which can be input to another. In my case it is not working coz the second command uses two words in it.
$ scr.sh
gives output like
193740
638102
375449
..
..
another command takes these number as inputs. it works great... (1 Reply)
Hi,
I am using below code snippet to echo/display the files found
(matching a pattern from searchstring.out file) and the corresponding owner.
while read j
do
echo "Pattern to search is:- $j"
find / -name "*$j*" |\
while read k
do
echo "File found is:- $k"
owner=$(ls... (9 Replies)
Since output of w command have variable number of columns I want to get the output in pipe delimited format. I tried
export OFS="|"; w
but that does not work.
Any ideas? (4 Replies)
Discussion started by: Soham
4 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)