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Full Discussion: Speeding up search and replace in a for loop
Top Forums Shell Programming and Scripting Speeding up search and replace in a for loop Post 302656659 by pbluescript on Friday 15th of June 2012 07:39:58 AM
Old 06-15-2012
Speeding up search and replace in a for loop
Hello,
I am using sed in a for loop to replace text in a 100MB file. I have about 55,000 entries to convert in a csv file with two entries per line. The following script works to search file.txt for the first field from conversion.csv and then replace it with the second field. While it works fine, it takes quite some time to run. Does anyone have any suggestions on how to speed it up?

Code:
while read LINE
do
  OLD=$( echo $LINE | cut -d, -f1 )
  NEW=$( echo $LINE | cut -d, -f2 )
  sed -i "s#\"$OLD\"#\"$NEW\"#g" file.txt
done < conversion.csv

 

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LEARN ABOUT DEBIAN

ifpps

ifpps(8)							netsniff-ng-toolkit							  ifpps(8)

NAME

       ifpps - fetch and format kernel network statistics

SYNOPSIS

       ifpps	 -d|--dev <netdev> [-t|--interval <sec>][-p|--promisc][-c|--term]
	    [-C|--csv][-H|--csv-tablehead][-l|--loop][-v|--version][-h|--help]

DESCRIPTION

       A tiny tool to provide top-like reliable networking statistics.	ifpps reads out the 'real' kernel statistics, so it does not give
       erroneous statistics on high I/O load.

OPTIONS

       ifpps --dev eth0
	   Fetch eth0 interface statistics.

       ifpps --dev eth0 --interval 60 --csv
	   Output eth0 interface statistics every minute in CSV format.

OPTIONS

       -h|--help
	   Print help text and lists all options.

       -v|--version
	   Print version.

       -d|--dev <netdev>
	   Device to fetch statistics for i.e., eth0.

       -p|--promisc
	   Put the device in promiscuous mode

       -t|--interval <time>
	   Refresh time in sec (default 1 sec)

       -c|--term
	   Output to terminal

       -C|--csv
	   Output in CSV format.  E.g. post-processing with Gnuplot et al.

       -H|--csv-tablehead
	   Print CSV table head.

       -l|--loop
	   Loop terminal output.

AUTHOR

       Written by Daniel Borkmann <daniel@netsniff-ng.org>

DOCUMENTATION

       Documentation by Emmanuel Roullit <emmanuel@netsniff-ng.org>

BUGS

       Please report bugs to <bugs@netsniff-ng.org>

								    2012-06-29								  ifpps(8)
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