I am having a trivial doubt. Please see the below pipeline code sequence.
Code:
command1 | (command 2; commend 3)
I am aware that the command that follows pipe will run in the sub shell by the Unix kernel. But how about here? Since these set of commands are grouped under "parantheses", will they run inside another sub shell of pipe's shell? Hope my question is not so be-wilder to be answered
Last edited by royalibrahim; 01-20-2010 at 02:33 PM..
can we use pipes to redirect the output of any command to grep .....
like i wanted to write this script about checking the online status of a certain user so ...can i send the output of who to grep directly using pipes...
one way was this :
who > temp
grep $uname temp
i was wondering if... (4 Replies)
Hi All
Here i have a piece of code,
set filename "./GopiRun.sh"
#I need to wait here until the GopiRun.sh is completed how do i achive this
exit. (1 Reply)
Hi Guys,
Just a question about subprocesses.. Lately one of our servers has started to throw out the following error:
SYSTEM ERROR: Too many subprocesses, cannot fork. Errno=12
We've already increased the threshold twice. Its now up to 8000 and the swap space has also been increased. We... (6 Replies)
Hi,
I am trying to run a shell script using subprocess in python.
I can run simple script with arguments using subprocess.But I am not able to embed xterm in subrocess command.
#!/usr/bin/python
import subprocess
subprocess.call()
Above code gives me error.
Please help me in... (2 Replies)
Hi guys,
I'm learning python and perl and i was trying to run from python a perl script using the subprocess module.
I have an issue that i don't understand regarding this.
I run this code:
#!/usr/bin/python
import subprocess
p2 = subprocess.Popen(,stdout=subprocess.PIPE)
output2 =... (2 Replies)
After struggling with this for days now, I'm reaching out to the experts of all things linux for some help with this.
I'm trying to run the following working command (on command line) inside a python script using subprocess:
rsync -avzh --no-perms --delete --include="*sub*" --exclude='*'... (2 Replies)
So I have this basic script, see below
import subprocess
import shlex
command = "gcloud projects list"
subprocess.check_output(shlex.split(command))
subprocess.check_call(shlex.split(command))
The subprocess.check_call(shlex.split(command)) actually return what I expect. It returns... (6 Replies)
Discussion started by: scj2012
6 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)
01-19-2010
