I didn't have ruby installed by default, I installed ruby, but that command produced an error I don't understand.
EDIT: @rdcwayx, Thanks, that works perfectly! And, I know bash better than ruby, (perl, python, etc.)
Ok, another fun hiccup in my UNIX learning curve. I am trying to count the number of occurrences of an IP address across multiple files named example.hits. I can extract the number of occurrences from the files individually but when you use grep -c with multiple files you get the output similar to... (5 Replies)
Hi All,
How can I work on following request?
Delete all the html files older than 29th November from the path - /dding/ting/tong/unixyang/output (4 Replies)
I am fully capable of reading a book to get the answers or looking to the web, but no one has the answer to this one. I had a Zoom 56K V34 Plus external modem (2836A) attached to my Unix box for about ten years without a flaw. This weekend I couldn't access the box remotely through the modem and... (0 Replies)
Good afternoon! Im new at scripting and Im trying to write a script to
calculate total space, total used space and total free space in filesystem names matching a keyword (in this one we will use keyword virginia). Please dont be mean or harsh, like I said Im new and trying my best. Scripting... (4 Replies)
Is there a size limit when passing an argument using wildcards? I.E. when I pass an argument in the form (like) "ftp_auto *.txt" - is there a limitation on the size of UNIX expanding "*.txt" ? (1 Reply)
I have a log file that I want to extract the field name and the field value
and write them to a text file for importation it a database table for reporting purposes.
How can I extract the desired data from this file .
Example: dbt_dbid=4
dbt_dbid is the field name
4 is the field value... (4 Replies)
I have a script that does log rotation, at 10000k, it will print out the logs as follows:
name.date.0.log(1gb)
name.date.1.log(1gb)
name.date.2.log(200mb) << current log being written to
at midnight it reverts back to : name.date.0.log(size)
I want it to be able to go past date.9.log... (2 Replies)
I even don't dare to ask for a hint, but as I am looking for clues may someone can help me, though reading me bsd handbook. It is about one machine running as media play studio with a debian distro and one machine running bsd 10.2 connected to one router.
By booting first the debian machine it... (4 Replies)
Discussion started by: 1in10
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)