This happens because the redirection has higher precedence than the rest of the operations so in the second case the file f1 is emptied before the cat command executes. If you want to achieve the same with redirection you'll need something like this:
hi, new to to forum...
i've been trying to create a script in tcsh but i'm having a problem with one thing...
the script has to keep log of it's input and output so i'm using
tee -a log | script | tee -a log
this keeps the logs as asked, but it gives me an extra empty prompt (not in the... (0 Replies)
Hi,
Is there anyway to duplicate output without using tee?
Let me explain the problem.
We are use ssh to login to remote server and save output to a file using tee commands for auditing purposes. When we use vi editor in ssh session, letters get garbled and cant really use vi. Without tee it... (7 Replies)
Hi,
I would like to process, filter the same ASCII asynchronous live data stream in more than one pipe pipeline.
So the one pipeline should filter out some records using grep key word
and more than one pipes pipelines
each should grep for another key words, each set seperately for each... (5 Replies)
I'm redirecting the output of a command to a logfile, however, if the user is on a terminal I would also like the output to be displayed on the screen.
tar tvf some_tarfile >Logfile
if the user is on a term then have the output to the Logfile and also be displayed on the screen at the same... (2 Replies)
Hi there
I have a script that runs but it outputs everything onto the screen instead of a file.
I've tried using the > outputfile.txt however all it does is dump the output to the screen and creates an outputfile.txt but doesn't put anything in that file.
Any help would be appreciated
... (6 Replies)
Hi,
When I run the following command in terminal it works. The string TEST is appended to a file silently.
echo TEST | tee -a file.txt &>/dev/null
However, when I paste this same line to a file, say shell1.sh, and use bourne shell .
I run this file in terminal, ./shell1.sh.
However I... (1 Reply)
We have an application here that does some table queries and then prints the result on screen. I do not have the code of this application (which i will just call "queryCommand"), but what it does is that you call it with some parameters and it prints some info about the query and then the... (5 Replies)
Hello i am trying to write a script that will redirect the output to a certain file. Here is the code so far:
#!/bin/bash
ps -e | sort | more > psfile
When I execute the script nothing happens since i assume the output was redirected to the file called psfile. When I try to look at the... (1 Reply)
Hi
I am making a script where i want to redirect the output of ls -l to a file
Example
#ls -l fil1.txt > /opt/temp/a.txt
ac: No such file or directory
I want to capture output of this command
like here output is
ac: No such file or directory
can anyone help (4 Replies)
Hi all
I was wondering if there was a slicker way of doing this without the file -
awk '{print $2}' FS=":" "${FILE}" > "${TMPFILE}"
{
read M_GRP_ID || m_fail 1 "Error: Read failed 1 (${FUNCNAME})"
read M_GRP_WAIT || m_fail 1 "Error: Read failed 2 (${FUNCNAME})"
}... (6 Replies)
Discussion started by: steadyonabix
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)