The above matches the longst string which ends in something which is not a member of [0-9]. It substitutes the match with "nothing". Thus it returns the rest of the line.
More precise would be to force it to start from the start of the line.
Hello There!
I am trying to write this SIMPLE script in Bourne Shell but I keep on getting syntax errors. Can you see what I am doing wrong? I've done this before but I don't see the difference. I am simply trying to take the day of the week from our system and when the teachers sign on I want... (7 Replies)
This "SHOULD" be a simple question,
but looking through several books has turned up nothing,
so I turn once again to the experts!!
How do you vi a file so that you can see special characters.
I believe my /etc/passwd file is being corrupted during an upgrade process, however the files... (6 Replies)
hi guys
trying to understand what this line means
sed is a stream editor and i understand that, i have a file already selected
i want to edit so i use -e
sed -e
the next stesp is s/$*
s is a subsititute replacement
sed -e s/$*//g
$ is in reference of the last line
/g makes it... (2 Replies)
Hi guys
sed -e "s/$<//g"
the $< can allow me to assign an input value to the variable right?
do the double quotes check the previous context? (1 Reply)
from command prompt I did grep two words on a same line for eg: grep abc | grep xyz and I got tht particular line, but I want to know when I vi that file how to directly search for that particular line? I appreciate if any one can provide answer, thanks in advance (2 Replies)
I have a line
EXTDIR=`echo $i | sed 's/\-tar.gz//'`
which looks for files ending in -tar.gz, i would like to increase the functionality so that it looks for .tar.gz files as well as -tar.gz. Do i put the - in square brackets with a dot ? like this
EXTDIR=`echo $i | sed 's/\tar.gz//'`
... (1 Reply)
hey,
Im just wondering is there away to get sed to read from a variable
eg
it doesn't seem to work, i really need to be able to recursively change the same data set... (2 Replies)
Hello,
I have the following line in one of my shell scripts. It works fine when the search string($SERACH_STR) exists in the logfile($ALERTLOG) but if the search string does not exist this line errors out at run time. Is there a way to make this line return 0 if it is not able to find the... (4 Replies)
Hi fellow linux-ers,
I have a quick question for you. I have the following text, which I would like to modify:
10 121E(121) 16 Jan
34S 132E 24 Feb
42 176E(176) 18 Sep
21S 164E 25 May
15 171W(-171) 09 Jul
How can I do the following 2 modifications using sed and/or awk?
1. in 1st column,... (1 Reply)
Discussion started by: lucshi09
1 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)