Hi All
In a script, I want a user to enter 4 characters, these can be a mix of letters (uppercase and lowercase) and numbers.
In this example $var represents what the user has entered.
eg $var can be A9xZ, 3DDL, bbHp .........etc
I need to check that the user has only entered characters... (2 Replies)
Hi,
I have trouble with quotations of the M4 preprocessor.
I want to write a basic makro that removes all spaces and newlines at the end and at the beginning of a string.
I tried this:
define(`TRIM_END', `patsubst(`$1', `\(\\n\| \)*$', `')')
define(`TRIM', `patsubst(`TRIM_END(`$1')',... (0 Replies)
Can someone explain the following? I can use find on *.pm without quotes, but find on *.pl makes on error, I need quotes for the second version. What's up with that?
$find -name *.pm
./tieProxyStatus/Status.pm
$find -name *.pl
find: paths must precede expression
Usage: find
$find... (2 Replies)
hi guys, i have a question related to quoting but i am not sure how to formulate it...
lets say we want to simulate the following shell actions
cd ~/project-dir
ctags /home/work/folder1/*.sh /home/work/folder2/*.sh /home/work/folder3/*.sh
so i make the following script
buidtags.sh
... (2 Replies)
I can do this on the command line:
sqsh -S 192.168.x.x -o tmp -U user -P fakepass -D horizon -C "\
select second_id
from borrower
where btype like '%wsd%'
"
I can also just leave the SQL at the end intact on one line ....
... However, when I throw this in a script like:
$SQSH -o... (4 Replies)
Hi all,
i have a file that looks like:
one:two:three:four:five
six:seven:eight:nine:ten
and i'd like to quote the fourth column, getting:
one:two:three:"four":five
six:seven:eight:"nine":ten
i was thinking something like:
awk 'BEGIN{FS=":"}{print $1 FS $2 FS $3 FS \"$4\" FS $5}'... (5 Replies)
I am writing a bash script to automate the installation of web environment on a base install of Fedora. And I'm at the limit of my last nerve and my bash skills. My brain is screaming at me: "Give up and use perl", but I am trying to stick to bash since the script will modify the perl environment... (6 Replies)
Hi,
I have got a file comp_data containing the below data :
38232836|9302392|49
39203827|8203203,3933203|52
72832788|567,3245,2434324|100
This file can have many rows like shown above. I want the values separated by "," in second column(taking "|" as delimiter) to be in quotes. These... (2 Replies)
I am trying to write a BASH script that will prompt a user to enter a number of days, then calculate the date.
My problem is the date command uses single or double quotes. For Example..
date -d "7 days"
Here is an example of some same code I am trying to work through.
echo "when do you... (4 Replies)
Discussion started by: javajockey
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)