Hi,
I need some help in removing the header (first line) and the trailer (last line) in a give file...
The data file actually comes in EBCDIC format and I converted it into ASCII..
Now I need to strip off the first line and the last line..
I think we can use sed to do something like this:... (2 Replies)
Aloha! I have just over 1k of users that have permissions that they shouldn't under our system. I need to parse a provided list of usernames, check their permissions file, and strip the permissions that they are not allowed to have. If upon the permissions strip they are left with no permissions,... (6 Replies)
Hi Folks,
I am new to ksh, i have informatica parameter file that i need to update everyday with shell script. i need your help updating this file with new parameters.
sample data
$$TABLE1_DATE=04-27-2011
$$TABLE2_DATE=04-23-2011
$$TABLE3_DATE=03-19-2011
.......Highligned... (4 Replies)
Hi! I have been struggling with a large file that has stray end of line characters.
I am working on a Mac (Lion). I mention this only because I have been mucking around with fixing my problem using sed, and I have learned far more than I wanted to know about Unix and Mac eol characters.
I... (1 Reply)
I have a test file with the following format, It contains the username_date when the user was locked from the database.
$ cat lockedusers.txt
TEST1_21062016
TEST2_02122015
TEST3_01032016
TEST4_01042016
I'm writing a ksh script and faced with this difficult scenario for my... (11 Replies)
Hi,
i have a file with multiple entries. After some tests with sed i managed to get the file output as follows:
lsn=X-LINK-IN0,apc=661:0,state=avail,avail/links=1/1,
00,2110597,2094790,0,81,529,75649011,56435363,
lsn=TM1ITP1-AM1ITP1-LS,apc=500:0,state=avail,avail/links=1/1,... (5 Replies)
Hello, i am trying to print group name column(etc/group) on script (etc/passwd) since group name is not listed on etc/passwd columns. Im trying to do a vlookup. but i cant figure out how i can insert the vlookup command FNR==NR inside the print out command or the output. I also tried exporting... (2 Replies)
Discussion started by: joonisio
2 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)