I'm having a problem when the first line or first character of a file is blank. I need to get rid of both of them when they occur but don't want to delete the line. Does anyone have any suggestions? (7 Replies)
if $1 = "123x456", how can I test for the non-numeric character 'x' in that string. I've tried expr with "" but it did not find the x. Any ideas? Can this perhaps be done with sed?
Thanks. (2 Replies)
how can i check whether variable contains only character from a-z or A-Z....if my variable contains any alpha numeric, numeric or any character with some special one i.e. *%&@! etcetera etcetera....then it should show me please enter only characters......
Let my variable
var1="abc77}|"
then... (9 Replies)
i am a newbie to shell script,so i want a kshell script in which i need to check for a particular character inside a file through conditional looping(like if ,case,while)and if that character exists ,then substitute a given character to that character.
consider a file test.txt,inside the file... (1 Reply)
Below is the abstract of the script which is working fine.
if ]
then
error_process "Invalid month format."
return 1
fi
I am doing validation for month and it errors if the value is > 12 or < 0. In addition, I want to add another condition to error if it... (2 Replies)
Hi,
I have a variable and to it always alphanumeric value will be assigned.
If the value has any special characters in it then in the if statement it should exit like below
if (value has any speacial character)
then
exit
else
....
fi
can any one suggest how to acheive this? (4 Replies)
I am working on a script to check the var on all of my systems. Can someone help me fix it to work better or give me suggestions.
#!/bin/ksh
IN=/path/to/list_of_workstations.txt
while read hostnames
do
if ping $hostnames 1 | grep alive > /dev/null
then
percent=`ssh -q... (3 Replies)
Discussion started by: whotippedmycow
3 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)