I am trying to extract a file using tar. I cd'ed to the directory I wanted to start in. I had the tar file in the same directory. I executed tar xvf filename . It appeared that it was extracting into the directory the tar file was created from instead of into the directory I was in. How do I... (1 Reply)
Hi,
Does anyone knows the command syntax for the following Unix commands:
at
mount
The OS is the Chorus/Mix 4.3 BSD Unix.
The "at" command does the following: at a precise date and hour it executes a desirede command.
Many thanks !!!
Regards, Pedro Pereira (3 Replies)
Here's my situation. I am trying to move all files from one directory to another. I have the following requirements:
1) Move all files in /myfiles/wip matching pattern "*.tif" to /work/in that are at least 10 minutes old (or older).
2) When the files are moved, they need to be moved into... (2 Replies)
Hi there.
I spent too much time away from Unix, now I can't remember how to issue a simple until command in ksh :mad:
could you tell me what is wrong with the following code sample:
export v = "1"
until
do
echo 'executing repeat_until'
v = `expr $v + 1`
done
I've... (3 Replies)
Can anyone tell me what the syntax is for the bind command in bash? I'm using OS X and the book i have ias written in 2005 ('Learning the bash shell') I'm guessing it was for an earlier version. It says something about single and double quotes, but I'm not sure exactly in what order they're... (2 Replies)
hi All,
how can i make my own commamnds for unix shell scripts.
lets xmple..
1-i want to use "down arrow key" for previous runned unix commands.
then how to acheive it.
2-Generally TAB --- complete filename or command up to the point of uniqueness ..but here its not working ..
I m new to... (1 Reply)
Hi all,
I want to add a shortcut "xmll" to my .cshrc file. By using "xmll" I want the following command to be executed:
find . -type f -name 'T*.xml' > xml_list.txt
BUT:
alias xmll 'find . -type f -name 'T*.xml' > xml_list.txt'
doesn't work.
What is the correct syntax?
Thank... (7 Replies)
Hey gang,
I'm confused about the 'exec' command. I get the basics. I can redirect stdout and stderr to one log file with:
exec >> $logFile 2>&1
However, that code requires admin rights. In other scripts, when faced with this, I'll call 'sudo' and then pass a hashed password like this:
... (8 Replies)
Discussion started by: hungryd
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)