04-01-2014
You did not say how much RAM you have, which is a definite factor.
The MD5 result is impressive. Is MD5 as cheap as a good hash? Perhaps CPUs have gotten so much faster than disk that it is not a factor!
In perl/C/C++/JAVA you can mmap the input file both for input and so your hash map can hold a 64 bit char* for exact verification, reducing copying and space allocation overhead.
The exact verification seems to expand the vm footprint a lot, but the most likely case is that the md5 or hash is new and so the exact compare is not done, greatly reducing processing and the vm footprint with a small minority of duplicates. If there were a lot of duplicates, that hurts the VM footprint with more exact verifications, but conversely there is less final data in the map.
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
I have a file which consists of 1000 entries. Out of 1000 entries i have 500 Duplicate Entires. I want to remove the first Duplicate Entry (i,e entire Line) in the File.
The example of the File is shown below:
8244100010143276|MARISOL CARO||MORALES|HSD768|CARR 430 KM 1.7 ... (1 Reply)
Discussion started by: ravi_rn
1 Replies
2. Shell Programming and Scripting
Hi,
My awk program is failing. I figured out using command
od -c filename
that the last line of the file doesnt end with a new line character.
Mine is an automated process because of this data is missing.
How do i handle this?
I want to append new line character at the end of last... (2 Replies)
Discussion started by: pinnacle
2 Replies
3. Shell Programming and Scripting
i have the long file more than one ns and www and mx in the line like .
i need the first ns record and first www and first mx from line .
the records are seperated with tthe ; i am try ing in awk scripting not getiing the solution.
... (4 Replies)
Discussion started by: kiranmosarla
4 Replies
4. Shell Programming and Scripting
Hi Sorry to multipost. I am opening the new thread because the earlier threads head was misleading to my current doubt.
and i am stuck.
list=`cat /u/Test/programs`;
psg "ServTest" | awk -v listawk=$list '{
cmd_name=($5 ~ /^/)? $9:$8
for(pgmname in listawk)
... (6 Replies)
Discussion started by: Anteus
6 Replies
5. Shell Programming and Scripting
I have an extremely large csv file that I need to search the second field, and upon matches update the last field...
I can pull the line with awk.. but apparently you cant use awk to directly update the file? So im curious if I can use sed to do this... The good news is the field I want to... (5 Replies)
Discussion started by: trey85stang
5 Replies
6. Shell Programming and Scripting
Folks ,
i want to read a csv file line by line till the end of file and filter the text in the line and append everything into a variable.
csv file format is :-
trousers:shirts,price,50
jeans:tshirts,rate,60
pants:blazer,costprice,40
etc
i want to read the first line and get... (6 Replies)
Discussion started by: venu
6 Replies
7. Shell Programming and Scripting
I have several hundreds of tiny files which need to be concatenated into one single line and all those in a single file. Some files have several blank lines. Tried to use this script but failed on it.
awk 'END { print r } r && !/^/ { print FILENAME, r; r = "" }{ r = r ? r $0 : $0 }' *.txt... (8 Replies)
Discussion started by: sdf
8 Replies
8. Shell Programming and Scripting
I'm looking to remove duplicate rows from a CSV file with a twist.
The first row is a header.
There are 31 columns. I want to remove duplicates when the first 29 rows are identical ignoring row 30 and 31 BUT the duplicate that is kept should have the shortest total character length in rows 30... (6 Replies)
Discussion started by: Michael Stora
6 Replies
9. UNIX for Dummies Questions & Answers
Hi all,
I've got a file that has 12 fields. I've merged 2 files and there will be some duplicates in the following:
FILE:
1. ABC, 12345, TEST1, BILLING, GV, 20/10/2012, C, 8, 100, AA, TT, 100
2. ABC, 12345, TEST1, BILLING, GV, 20/10/2012, C, 8, 100, AA, TT, (EMPTY)
3. CDC, 54321, TEST3,... (4 Replies)
Discussion started by: tugar
4 Replies
10. Shell Programming and Scripting
My file (the output of an experiment) starts off looking like this,
_____________________________________________________________
Subjects incorporated to date: 001
Data file started on machine PKSHS260-05CP
**********************************************************************
Subject 1,... (9 Replies)
Discussion started by: samonl
9 Replies