First off, unix filesystems cannot have a filename that is just the nul (ASCII 0) character,
unless the filesystem has been badly corrupted. In other words if you have "noname" files they are probably files that have unprintable characters in the name.
If you think the filesystem has been corrupted, use fsck or a similar tool to check it.
This will find files that have at least one blank (ASCII 32 character ) in the name:
If you have an all blanks (1 blank ... n blanks) filename the output of ls looks like this:
Note the "empty" spot.
Hello,
I actually have two issues. First, here is the file the way it is now.
someword someword:1
new-word new-word abcd
someword someword:10
new-word new-word abcd
thisis whatIneed:3
someword someword:5
new-word new-word abcd
I need to get the line before the 2... (6 Replies)
Hi all,
I have a huge file and I need to get ride of the fields 6-11 and replace the blanks in field 5 with a missing value(99999).
159,93848,5354,343,67898,45,677,5443,434,5545,45
677,45545,3522,244,
554,54344,3342,456,
344,43443,2344,444,23477... (12 Replies)
I need to find empty files in a directory and write them into a text file. Directory will contain old files as well, i need to get the empty files for the last one hour only. (1 Reply)
Hi Guys,
Can any one help me on this,
I want to write unix command to get all .sh unix file name which are refered .sql files in it.
Thanks
Kolipaka (3 Replies)
Find a blank field
Hi
I have set of fields that have some blank values, how to find that and get its line noumbers in output file.
Ex:
Col1 col2 col3
11 ss 103
12 104
13 105
14 se 106 (2 Replies)
Hi All,
I want to find the difference between two files, by checking only the headers (column names) and report if any new column is added in the latest file.
For Ex: If the file "declartion.txt has these columns
url;image;id;showcase_id;showcase_name
and the actual file "feed.txt" has... (34 Replies)
Data files coming in different names in a file name called process.txt.
1. shipments_yyyymmdd.gz
2 Order_yyyymmdd.gz
3. Invoice_yyyymmdd.gz
4. globalorder_yyyymmdd.gz
The process needs to discard all the below files and only process two of the 4 file names available
... (1 Reply)
Hi
I have file "emp.txt"like below
Emp Id Name
123 aa
123 bb
223 cc
233 dd
334 ee
Please help me to know that the position of the blank row. (5 Replies)
I have a text file downloaded from the web, I want to count the unique words used in the file, and a person's speaking length during conversation by counting the words between the opening and closing quotation marks which differ from the standard ASCII code. Also I found out the file contains some... (2 Replies)
Discussion started by: yifangt
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)