Hi! I'm using
echo $string | grep "" -c
to test in a script if a string is a number and it seems to work. But how can i find, for example, if a string is a four figures number ?
Thanks to all! (2 Replies)
Okay, well this is more or less my first attempt at writing a shell script.
Anyways, here's my code:
cd ${PATH}
if
then
rm ${FILE}
./anotherScript
else
exit 1
fi
exit 1
Anyways, it's a pretty simple script that is supposed to search for the... (4 Replies)
This is the code:
while test 1 -eq 1
do
read a
$a
if test $a = stop
then
break
fi
done
I read a command on every loop an execute it.
I check if the string equals the word stop to end the loop,but it say that I gave too many arguments to test.
For example echo hello.
Now the... (1 Reply)
Hello all,
I'm trying to automate an if statement in my Perl script. The script opens an input file for reading, checks each line in the file for a particular substring, and if it finds the substring, writes it to an output file.
There are approximately 200 different input files. Each has... (3 Replies)
Hello,
I am trying to build a test statement but I can't make it work
I want to rearrange some fields, so if my "$cfg" variable contains a string ending with .log (*.log) I want to move it in another field.
Any help will be much appreciated!
Thank you
Shell:sh
if
then
log="${cfg}"... (9 Replies)
Is it possible to test against a varible within a ranges in a if statement.
ex.
if ];then
echo "not in range"
else
echo "number within range"
fi (8 Replies)
Discussion started by: leemalloy
8 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)