${#parameter}
The length in characters of the value of parameter is substi‐
tuted. If parameter is * or @, the value substituted is the
number of positional parameters. If parameter is an array name
subscripted by * or @, the value substituted is the number of
elements in the array.
I'm trying to check if files already exist in a directory. They have the same basename (exsyctr1), but 4 different extensions. If the files exist, then I make backups of them, then copy them from another directory ($livecomp/data) to the current one ($copycomp/data). If they don't exist, just... (5 Replies)
Howdie everyone...
I have a shell script RemoveFiles.sh
Inside this file, it only has two commands as below:
rm -f ../../reportToday/temp/*
rm -f ../../report/*
My problem is that when i execute this script, nothing happened. Files remained unremoved. I don't see any error message as it... (2 Replies)
I have a text file that contains lines similar to the following:
-----------------------------------------------------------
fall for setup
CSHRC0 'gnd';
CSHR0 'gnd';
rise for setup
rise for hold
CSHRC0 'gnd';
CSHR0 'gnd';
fall for hold ... (4 Replies)
$var=`command <arg> <arg>`
I thought there was another method
$var=$(command <arg> <arg>)
I thought I read saw the second example. It doesnt work (2 Replies)
I have a large file encoded in Unicode that I need to convert to CSV. In general, I know how to do this by regular expression substitutions using sed or Perl, but one problem I am having is that I need to put a quotation mark at the end of each line to protect the last field. The usual regex... (1 Reply)
Hi,
I'm a bit stuck trying to get my sed syntax quite right for what I'm trying to do.
I have a list of directories in a file and am trying to remove some of them using sed. I can do it if I specify the directory I want to remove in the sed command and escape the "/"s like so:
say I... (2 Replies)
I have a client machine that was built and loaded with SCO UNIX 2.1.3, (yes it is old). The machine worked fine on the closed network that I tested on in my shop. I then had to change it to the network that it would be connected to. Below is the host file, router and subnet mask file that I usually... (0 Replies)
My script work on Linux but not work in sun os.
my script.
logFiles="sentLog1.log sentLog2.log"
intial_time="0 0"
logLocation="/usr/local/tomcat/logs/"
sleepTime=600
failMessage=":: $(tput bold)Log not update$(tput rmso) = "
successMessage="OK"
arr=($logFiles)... (7 Replies)
Hi all,
I basically want to remove certain characters from within a certain XML tag:
From:
<mytagone>hello 1-2-3 world</mytagone>
<mytagtwo>hello 1-2-3 world</mytagtwo>
To:
<mytagone>hello 1 2 3 world</mytagone>
<mytagtwo>hello 1-2-3 world</mytagtwo>
Is this possible using sed... (6 Replies)
hi all. and sorry for the random question, but this sparkled a raging flame-war at work and i want more points of view
situation
a router, with linux of some sort,
dhcp client requesting for ip in wan1 (as usual with wan ports)
dhcp server listening in lan1, and assigning ip (as usual... (9 Replies)
Discussion started by: broli
9 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)