I asked what the users.db looked like too, and noted that my grep solution probably doesn't do what you want because I don't know what users.db looks like...
Code:
while true
do
read ID
if [ "${#ID}" -ne 3]
then
echo "wrong number of digits"
continue
fi
if ! [ -z "${ID/[0-9]*/}" ]
then
echo "Not all digits"
continue
fi
if grep "$ID" users.db > /dev/null
then
echo "The string '$ID' exists anywhere at all in users.db"
continue
fi
break # get out of loop
done
Hi All,
I have absolutely no experince with either one, and would LOVE to start from somewhere! So please guide me to some web sites (beside these great forums of course!) that I can obtain n00b information. (Books, links, resources, etc.)
What software OS? should I begin with? I have heard... (2 Replies)
Hi,
have a basic query.
Please see the below code:
list="one two three"
for var in $list ; do
echo $var
list="nolist"
Done
Wht if I want to print only first/ last line in the list
Eg one & three
Regards
er_ashu (3 Replies)
need some help badly.
if i had a file with content of few lines like the followings.
1183724770.651 0.049 137.157.56.169 200 415 GET http://venus/client/clients.xml "text/xml"
1183724770.651 0.049 141.183.101.250 200 415 GET http://venus/client/clients.xml "text/xml"
using what command... (1 Reply)
Hey guys,
This is quite simply what I'm trying to make:
A program that runs in a UNIX terminal that you can output text messages to from another machine. These text messages would be prepended with a customized prompt. I'd also like to have the window spew out random dumps of flavor text not... (1 Reply)
Hey Guys!
I was hoping for some help with a simple script I'm trying to use. I have the script set up to pull some simple information out of a database .txt file and sed it into a preexisting template for assignment cover letters. The problem seems to be someplace in the sed statement but I... (5 Replies)
Howdy People :),
I'm a newbie & its my first question here. I've started learning Unix Bourne Shell scripting recently and struggling already :p Can someone PLEASE help me with the following problem. Somehow my script is not working.
Display an initial prompt of the form:
Welcome to... (1 Reply)
Hi,
I am very new to this forum, can any one tell me which is the very basic certification on unix shell scripting?
please give me an advice on this. (1 Reply)
I need to read input from a file, and make sure nothing prints after column 72.
basically, ignore input after character 72 until the next newline character.
Any help is appreciated. I have been searching forever! (10 Replies)
Hi,
Sorry if this is a newbie question. I guess you can use either awk or shell script for this sequence of operations, but knowing very little about either of them I'm not sure how I should try to write this.
The basic objective is to copy certain files that are scattered all over my... (10 Replies)
Oracle Linux : 6.4/bash shell
In the below I want to break out of the loop when it enters the 5th iteration.
#!/bin/bash
for i in 1 2 3 4 5 6
do
echo "$i"
if
echo "Oh Nooo... i = $i. I need to stop the iteration and jump out of the loop"
then break
fi
done
But, it only... (3 Replies)
Discussion started by: John K
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)