Note that with 20 fields on each of 3,000 input records being combined into 200 output lines, your average output lines with have 300 fields and some lines could have many more. You don't give us any indication of what system you're using, nor of the contents of most of the input fields. The awk utility and most editors are only defined to work on text files, and by definition, lines in a text file can't be longer than LINE_MAX bytes (including the terminating newline character). (Try:
to determine the value of LINE_MAX on your system. The standards only require that implementations support lines up to 2,048 bytes per line.) Are you sure that none of your output lines exceed LINE_MAX?
If you ask awk to print a line that is longer than LINE_MAX bytes long, the results are unspecified. If you use ed, ex, grep, sed, vi (or any of LOTS of other standard utilities that are described as processing text files) to read or write or create internal lines longer than LINE_MAX bytes long, the results are unspecified. There are very few standard text processing utilities that are defined to work on lines with arbitrary lengths (cut, fold, and paste).
Can some-one give me a view to this :
I have a directory in an unix server, having permissions r-xr-xr-x .This directory is basically a source directory.
Now there is another directory basically the destination directory which has all the permissions.
Note:I log in as not the owner,but user... (5 Replies)
$ echo a.bc | sed -e "s/\|/\\|/g"
|a|.|b|c|
$
Is the behavior of the sed statement expected ? Or is this a bug in sed ?
OS details
Linux 2.6.9-55.0.0.0.2.ELsmp #1 SMP Wed May 2 14:59:56 PDT 2007 i686 i686 i386 GNU/Linux (8 Replies)
Hi All,
I got a strange problem here. I have a perl script which is fetching data from a database table and writing a file with that data.
If i run that script from linux command line, the file it creates is a normal ascii text file without any binary character in it.But... (9 Replies)
Hello,
I was trying to identify lines who has a word of the following pattern "xyyx" (where x, and ys are different characters).
I was trying the following grep -
egrep '(\S)()\2\1'
This pattern do catches the wanted pattern, but it also catches "GGGG" or "CCCC" patterns. I was trying to... (5 Replies)
Hi,
We have a problem where occasionally an ssh will hang for no apparent reason preventing the rest of the script continuing. To deal with this I am trying to write a wrapper script to kill a hung ssh command after a specified period.
The scripts use a sleep command running in the... (2 Replies)
Hi,
Today I have found the following case in perl:
print "length:$lengths\tsum:". $count{$lengths}+$count_pair{$lengths}."\tindi:$count{$lengths}\t$count_pair{$lengths}\n";This give output as That means the first part of print is not printing. Only the values after the additions are printed.... (5 Replies)
Can someone please explain the strange behaviour.. I was just trying a few things to learn awk..
in the below code when I start the braces in the same line, the output is as expected, when I start at next line, output is displayed twice.
Please see the file, code I tried and output below.
... (2 Replies)
Hello All,
I have a text file containing output from a command that contains lots of escape/control characters that when viewed using vi or view, looks like jibberish. But when viewed using the cat command the output is formatted properly.
Is there any way to take the output from the cat... (7 Replies)
Discussion started by: mrm5102
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)