I'm very new to Sed and I have a very large file that contains data in the following way
Essentially what I want to do it delete every line that starts with
I tried the following,
But this doesn't work. I'm not sure whether this is because the start of the line contains special characters (forward bracket and the asterix) or whether there is a space before 1.
Hi all,
I am trying to figure out the syntx to delete multiple lines w/ sed. I know the following syntax will delete lines 1 THROUGH 5 from filex:
sed 1,5d filex
But I wan to delete lines 1 AND 5 (keeping lines 2,3, and 4). Does anyone know how to do this in a single sed statement?
... (2 Replies)
I have been reading through the sed one liners, trying to understand what is happening.
# delete the last 2 lines of a file
sed 'N;$!P;$!D;$d'
The above will delete the last 2 line of a file. I tried analyzing what happens. And I got lost :(
This is what I understood so far from the... (2 Replies)
hello all
I have bunch of files containing lines of text that surrounding by <# .......#> tags
I like to delete this lines from the text files whiteout open the files , can it be done with sed ?
or other unix tool (perl mybe )? (2 Replies)
I have a text file with blank lines fullfilled with spaces and others only containing the "Enter" caracter, the \012.
I would like to eliminate all them with the sed command.
Is it possible?
making: sed '/^$/d' <file should delete the blank lines but doesn't work for the lines that only... (2 Replies)
First of all, I know this can be more eassily done with perl or other scripting languages but, that's not the issue. I need this in sed. (or wander if it's possible )
I got a file (trace file to recreate the control file from oracle for the dba boys)
which contains
some lines
another line... (11 Replies)
Hi All,
I have one /etc/hosts.equiv file which has following entries
##########
wcars42g admin
wcars42b netmgr
wcars42b oemssrvr
wcars42f admin
wcars42f netmgr
wcars42f oemssrvr
##########
I am trying to delete lines starting from wcars42b.... (1 Reply)
Hello everyone I'm doing a program in bash and wanted to know how can I do to delete document lines the words not ending in S with SED, ie, show only those ending with the letter S.
I probe with:
sed -e /$.*/d "$file" | more
to delete all lines NOT ending in S but not work!... (3 Replies)
Hello,
I'm trying to figure out how to use sed or awk to delete single lines in a file. By single, I mean lines that are not touching any other lines (just one line with white space above and below).
Example:
one
two
three
four
five
six
seven
eight
I want it to look like: (6 Replies)
Hi Members,
This is my first post in this forum.
I want to do is match form feed lines one by one in a file and delete the next n lines (ex-3 lines) with the form feed character
Eg - Files looks like
Data 1
Data 2
Data 3
FF
Hdr1
Hdr2
Hdr3
Data4
Data5
FF
Hdr1
Hdr2
Hdr3 (9 Replies)
Discussion started by: yohan
9 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)