given a string passed to a program that supposed to be numeric and of a certain length say 8 digits - so say for e.g. need to verify this 01234567
How would I parse this string to validat it meet requirements
I tried to use * | sed /\(\{8})/
Thanks in advance (1 Reply)
Hello,
I really would appreciate some help with a bash script for some string manipulation on an SQL dump:
I'd like to be able to rename "sites/WHATEVER/files" to "sites/SOMETHINGELSE/files" within the sql dump.
This is quite easy with sed:
sed -e... (1 Reply)
Hi all,
I am trying to find the best way of making a change to 1 char in a string, the string can be between 1 and 14 characters.
I am reading a line in from a file which contains
012341231231:2:102939283:NNN: Require :NBN:
012838238232:3:372932:NNN: Require :NNB:
I need to change 1 N or a... (8 Replies)
Can someone tell me how to change the first column in a very large 17k line file from a random 10 digit numeric value to a non numeric value. The format of lines in the file is:
1702938475,SNU022,201004
the first 10 numbers always begin with 170 (6 Replies)
Hi guys
I am having this strange issue.Well my requirement is like below
Compare two values between flat file and oracle DB
Via perl script I am easily getting the rowcount
Now I connect sql plus via perl and the column value that returns is string
my $sqlplus_settings = '';
my... (7 Replies)
I have a string like
Months=jan feb mar april x y ..
Here the number of fields in Months is not definite
I need to extract each field in the Months string and pass it to awk . Don't want to use for in since it is a loop . How can i do it (2 Replies)
Hello,
I've a file file_1.txt
ul.ln = 'Kb' AND (il.sum = 'ec7ccc92585adac28d9b1fb5eff0473f' or length('ec7ccc92585adac28d9b1fb5eff0473f') = 7);
il.sum = '20ddc1368d588dd0b0e37c41721e05b1' OR length('20ddc1368d588dd0b0e37c41721e05b1') = 7);
I need to replace the file like below -
ul.ln... (4 Replies)
My sample file is variable length, with out any field delimiters. It has min of 18 chars length and the 'CRLF' is potentially between 12-14 chars. How do I replace this with a space? I still want to keep end of record, but just want to remove these new lines chars in the middle of the data.
... (7 Replies)
Discussion started by: chandrath
7 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)