03-31-2016
sed solution is fastest, doubt you'll be able to beat it by much (virutally immeasurable).
Maybe if we understood what you're wanting to do with the middle data?
This User Gave Thanks to cjcox For This Post:
9 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
Hello,
I need to insert a line (like a header) as the first line of a very huge file (about 3 ml rows). I am able to do it with sed, but redirecting the output and creating a new file takes quite some time. I was wondering if there was a more efficient way of doing it?
Any help would be... (3 Replies)
Discussion started by: shriek
3 Replies
2. UNIX for Dummies Questions & Answers
i need help..!!!!
i have one big text file estimate data file size 50 - 100GB with 70 Mega Rows.
on OS SUN Solaris version 8
How i can remove first line of the text file.
Please suggest me for solutions.
Thank you very much in advance:) (5 Replies)
Discussion started by: madoatz
5 Replies
3. Shell Programming and Scripting
So, I want to read line-by-line a text file with unknown number of files....
So:
a=1
b=1
while ; do
b=`sed -n '$ap' test`
a=`expr $a + 1`
$here do something with b etc
done
the problem is that sed does not seem to recognise the $a, even when trying
sed -n ' $a p'
So, I cannot read... (3 Replies)
Discussion started by: hakermania
3 Replies
4. Shell Programming and Scripting
I have file which contains around 5000 lines.
The lines are fixed legth but having no delimiter.Each line line contains nearly 3000 characters.
I want to delete the lines
a> if it starts with 1 and if 576th postion is a digit i,e 0-9
or
b> if it starts with 0 or 9(i,e header and footer)
... (4 Replies)
Discussion started by: millan
4 Replies
5. Shell Programming and Scripting
Hi Experts,
I had to edit (a particular value) in header line of a very huge file so for that i wanted to search & replace a particular value on a file which was of 24 GB in Size. I managed to do it but it took long time to complete. Can anyone please tell me how can we do it in a optimised... (7 Replies)
Discussion started by: manishkomar007
7 Replies
6. Shell Programming and Scripting
Hi,
I have a huge file with a single line.
But I want to break that line into lines of with each line having five columns.
My file is like this:
code:
"hi","there","how","are","you?","It","was","great","working","with","you.","hope","to","work","you."
I want it like this:
code:... (1 Reply)
Discussion started by: rajsharma
1 Replies
7. Shell Programming and Scripting
We have a huge file which has just one really large line; about 500 MB. I want to
1. Count all the occurrences of a phrase
2. Replace the phrase with another.
Trying to open it using vi has not helped as it complains that it is too large. Can any script help? Please advise.
Thank you, (12 Replies)
Discussion started by: kaushikadya
12 Replies
8. Shell Programming and Scripting
Hi,
I want to read a live log file line by line and considering those line which start from time stamp;
Below code I am using, which read line but throws an exception when comparing line that does not contain error code
tail -F /logs/COMMON-ERROR.log | while read myline; do... (2 Replies)
Discussion started by: ketanraut
2 Replies
9. UNIX for Dummies Questions & Answers
Hi ,
I would like to replace new line characters(\n) in a huge file of about 2 million records . I tried this one (:%s/\n//g) but it's hanging there and no result. Does this command do not work if the file is big. Please let me know if you have any other options
Regards
Raj (1 Reply)
Discussion started by: rajeevm
1 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)