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Full Discussion: Incredibly inefficient cat | grep script
Top Forums Shell Programming and Scripting Incredibly inefficient cat | grep script Post 302913041 by Cludgie on Wednesday 13th of August 2014 12:50:06 PM
Old 08-13-2014
Incredibly inefficient cat | grep script
Hi there,

I have 2 files that I am trying to work on.

File 1 contains a reference list of unique subscriber numbers ( 7 million entries in total)

File 2 contains a list of the subscriber numbers and their tariff (15 million entries in total). This file is in the production system and hasn't had old subscribers removed for some time so more than half of the entries need removed.

I created the following couple of lines to try to obtain the active 7 million subscriber numbers and tariffs from the behemoth 15 million list

Code:
 cat accurate_list.csv | while read ref
> do
> grep $ref production_list.csv >> new_msisdn_list.csv
> done

While this is actually working, it's only producing around 20 entries per second, which will take days to complete.

I'm afraid I'm a complete noob and can't come up with anything more inventive. I'm sure awk/sed/perl or probably any other number of languages would be perfect for something like this.

Anyway any suggestions are gratefully received.

Thanks
Cludgie
 

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LEARN ABOUT DEBIAN

numsum

NUMSUM(1)						User Contributed Perl Documentation						 NUMSUM(1)

NAME

       numsum - numsum program file

SYNOPSIS

       numsum [-iIcdhrsvxy] <FILE>

       | numsum [-iIcdhrsvxy]	(Input on STDIN from pipeline.)

       numsum [-iIcdhrsvxy]	(Input on STDIN.  Use Ctrl-D to stop.)

DESCRIPTION

       numsum will take all the numbers on stdin and return the sum of those numbers.  Currently it only processes the first number on each line.
       Besides positive numbers, it also handles negative numbers and numbers with decimals.

OPTIONS

	   -i  Only return the integer portion of the final sum.
	   -I  Only return the decimal portion of the final sum.

	   -c	   Print out the sum of each column.
	   -r	   Print out the sum of each row.

	   -x <n>  Specify a comma seperated list of columns to print.
	   -y <n>  Specify a comma seperated list of rows to print.

	   -s <string> Specify a string to use as a seperator for columns.
		       This defaults to be consecutive whitespace (s+).

	   -h  Help: You're looking at it.
	   -V  Increase verbosity.
	   -d  Debug mode.  For developers
	   -q  Quiet mode, don't print any warnings.

EXAMPLES

       Simply add up the numbers in a file.
	   $ numsum numbers.txt
	   4315

       Enter your own numbers on STDIN. The last number is the answer.
	   $ numsum
	   4
	   21
	   98
	   100
	   223

       Use it in a command pipeline.
	   $ ls -1s | grep .mp3 | numsum -c -x 5
	   72288

       Add up the total byte count in a http log file.
	   $ cat access_log | awk {'print $10'} numsum

	   or

	   numsum -c -x 10 access_log

       Add up the columns of numbers of a file.

	   $ cat columns
	   1 6 11 16 21
	   2 7 12 17 22
	   3 8 13 18 23
	   4 9 14 19 24
	   5 10 15 20 25
	   $ numsum -c columns
	   15 40 65 90 115

       Add up the 1st, 2nd and 5th columns only.

	   $ numsum -c -x 1,2,5 columns
	   15 40 115

       Add up the rows of numbers of a file.

	    $ numsum -r columns
	    55
	    60
	    65
	    70
	    75

       Add up the 2nd and 4th rows.

	    $ numsum -r -y 2,4 columns
	    60
	    70

SEE ALSO

       numaverage(1), numbound(1), numinterval(1), numnormalize(1), numgrep(1), numprocess(1), numrandom(1), numrange(1), numround(1)

COPYRIGHT

       numsum is part of the num-utils package, which is copyrighted by Suso Banderas and released under the GPL license.  Please read the COPYING
       and LICENSE files that came with the num-utils package

	 Developers can read the GOALS file and contact me about providing
       submitions or help for the project.

MORE INFO

       More info on numsum can be found at:

       http://suso.suso.org/programs/num-utils/

perl v5.10.1							    2009-10-31								 NUMSUM(1)
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