Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Incredibly inefficient cat | grep script
Top Forums Shell Programming and Scripting Incredibly inefficient cat | grep script Post 302913160 by MadeInGermany on Thursday 14th of August 2014 07:31:24 AM
Old 08-14-2014
With your new information, you can speed up Corona's perl solutions with awk:
Code:
pipesplit.pl -l 5000 awk 'FILENAME=="-" {A[$1]; next} ($1 in A)' - FS="," production_list.csv < accurate_list.csv

The hash lookups are faster than an RE that can match anywhere in the lines.
Also, increasing the 5000 by a factor 10 will increase speed (and memory consumption) by the same factor.
BTW I find the following order more intuitive:
Code:
< accurate_list.csv pipesplit.pl -l 5000 awk 'FILENAME=="-" {A[$1]; next} ($1 in A)' - FS="," production_list.csv

Last edited by MadeInGermany; 08-14-2014 at 08:40 AM.. Reason: added the missing FS=","
This User Gave Thanks to MadeInGermany For This Post:
Corona688
 

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

cat and grep not working

I am trying to cat a file and then grep that file for a number. I can do it fine on other files but this particular file will not do anything. I tried running it on an older file from the same device but it is just not working. The file is nothing more than a flat file on a unix box. Here is just a... (3 Replies)
Discussion started by: jphess
3 Replies

2. Shell Programming and Scripting

cat in the command line doesn't match cat in the script

Hello, So I sorted my file as I was supposed to: sort -n -r -k 2 -k 1 file1 | uniq > file2 and when I wrote > cat file2 in the command line, I got what I was expecting, but in the script itself ... sort -n -r -k 2 -k 1 averages | uniq > temp cat file2 It wrote a whole... (21 Replies)
Discussion started by: shira
21 Replies

3. Shell Programming and Scripting

Perl sum really inefficient!!

Hi all, I have a file like the following: ID, 2,Andrew,0,1,2,3,4,2,5,6,7,7,9,3,4,5,34,3,2,1,5,6,78,89,8,7,6...................... 4,James,0,6,7,0,5,6,4,7,8,9,6,46,6,3,2,5,6,87,0,341,0,5,2,5,6.................... END, (there are more entires on each line but to keep it simple I've left... (10 Replies)
Discussion started by: Donkey25
10 Replies

4. Shell Programming and Scripting

Problem with IF - CAT - GREP in simple shell script

Hi all, Here is my requirement I have to search 'ORA' word in out.log file,if it is present then i need to send that file (out.log) content to some mail id.If 'ORA' word is not in that file then i need to send 'load succesful' message to some mail id. The below the shell script is not... (5 Replies)
Discussion started by: mak_boop
5 Replies

5. Shell Programming and Scripting

cat /etc/passwd and grep -v on /etc/shells

Hi All, I'd like to do this cat /etc/passwd and grep -v on the /etc/shells list I'd like to find all shell that doesn't exist on the /etc/passwd. Is there an easy way without doing a egrep -v "/bin/sh|/bin/bash................"? How do I use a file /etc/shells as my list for... (4 Replies)
Discussion started by: itik
4 Replies

6. Shell Programming and Scripting

cat -n and grep

I am not sure if using cat -n is the most efficient way to split a file into multiple files, one file per line in the source file. I thought using cat -n would make it easy to process the file because it produces an output that numbers each line that I could then grep for with the regex "^ *$i".... (3 Replies)
Discussion started by: kapu
3 Replies

7. Shell Programming and Scripting

grep or cat using sed

Is there a way using grep or cat a file to create a new file based on whether the first 9 positions of each record is less than 399999999? This is a fixed file format. (3 Replies)
Discussion started by: ski
3 Replies

8. UNIX for Dummies Questions & Answers

Grep and cat combined

Hello, i need to search one word (snp1) from many files and copy the content of the columns of this word in new file. example: file 1: SNP BP CHR P snp1 1 3 0.01 snp2 2 2 0.05 . . file 2: SNP BP CHR P snp1 1 3 0.06 snp2 2 2 0.3 output... (6 Replies)
Discussion started by: biopsy
6 Replies

9. Shell Programming and Scripting

Replace cat and grep with <

Hello someone told me to use OS=`awk '{print int($3)}' < /etc/redhat-release` instead of OS=cat /etc/redhat-release | `awk '{print int($3)}'` any idea for the reason ? (5 Replies)
Discussion started by: nimafire
5 Replies

10. UNIX for Dummies Questions & Answers

Grep or cat The Whole Directory PROBLEMS :(

Hi Guys This is my first post so I am not sure how things go here. I'm sorry if I'm breaking the rule or something. Feel free to correct me about that :) So as I was saying... I'd been trying to grep this folder containing 900,000 txt files but seems no luck. I get either "No such file... (6 Replies)
Discussion started by: Nexeu
6 Replies

LEARN ABOUT CENTOS

processcsv.py

PROCESSCSV.PY(1)					      Virtualization Support						  PROCESSCSV.PY(1)

NAME

       processcsv.py - process virt-top CSV files

SUMMARY

	virt-top --csv data.csv
	processcsv.py < data.csv

DESCRIPTION

       virt-top is a top(1)-like utility for showing stats of virtualized domains.

       processcsv.py is a simple Python script that post-processes the output of "virt-top --csv".

       It is used like this:

	virt-top --csv data.csv
	processcsv.py < data.csv

       The second command will overwrite the following files in the current directory:

       "global.csv"
	   This contains the global (host) statistics columns from the CSV file.

       "domainNN.csv" (multiple files)
	   For each libvirt domain ID NN, a file is created containing the per-domain statistics from the CSV file.

SEE ALSO

       virt-top(1)

AUTHORS

       Richard W.M. Jones <rjones @ redhat . com>

COPYRIGHT

       (C) Copyright 2007-2012 Red Hat Inc., Richard W.M. Jones http://libvirt.org/

       This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
       the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation,
       Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

virt-top-1.0.8							    2013-12-29							  PROCESSCSV.PY(1)
All times are GMT -4. The time now is 04:02 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy