Sponsored Content
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

 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Perl: Search for string on line then search and replace text

Hi All, I have a file that I need to be able to find a pattern match on a line, search that line for a text pattern, and replace that text. An example of 4 lines in my file is: 1. MatchText_randomNumberOfText moreData ReplaceMe moreData 2. MatchText_randomNumberOfText moreData moreData... (4 Replies)
Discussion started by: Crypto
4 Replies

2. UNIX for Dummies Questions & Answers

Speeding up a Shell Script (find, grep and a for loop)

Hi all, I'm having some trouble with a shell script that I have put together to search our web pages for links to PDFs. The first thing I did was: ls -R | grep .pdf > /tmp/dave_pdfs.outWhich generates a list of all of the PDFs on the server. For the sake of arguement, say it looks like... (8 Replies)
Discussion started by: Dave Stockdale
8 Replies

3. Shell Programming and Scripting

awk - replace number of string length from search and replace for a serialized array

Hello, I really would appreciate some help with a bash script for some string manipulation on an SQL dump: I'd like to be able to rename "sites/WHATEVER/files" to "sites/SOMETHINGELSE/files" within the sql dump. This is quite easy with sed: sed -e... (1 Reply)
Discussion started by: otrotipo
1 Replies

4. Programming

PERL, search and replace inside foreach loop

Hello All, Im a Hardware engineer, I have written this script to automate my job. I got stuck in the following location. CODE: .. .. ... foreach $key(keys %arr_hash) { my ($loc,$ind,$add) = split /,/, $arr_hash{$key}; &create_verilog($key, $loc, $ind ,$add); } sub create_verilog{... (2 Replies)
Discussion started by: riyasnr007
2 Replies

5. UNIX for Dummies Questions & Answers

Speeding/Optimizing GREP search on CSV files

Hi all, I have problem with searching hundreds of CSV files, the problem is that search is lasting too long (over 5min). Csv files are "," delimited, and have 30 fields each line, but I always grep same 4 fields - so is there a way to grep just those 4 fields to speed-up search. Example:... (11 Replies)
Discussion started by: Whit3H0rse
11 Replies

6. Shell Programming and Scripting

perl search and replace - search in first line and replance in 2nd line

Dear All, i want to search particular string and want to replance next line value. following is the test file. search string is tmp,??? ,10:1 "???" may contain any 3 character it should remain the same and next line replace with ,10:50 tmp,123 --- if match tmp,??? then... (3 Replies)
Discussion started by: arvindng
3 Replies

7. Shell Programming and Scripting

search replace with loop and variable

Hi, could anyone help me with this, tried several times but still not getting it right or having enough grounding to do it outside of javascript: Using awk or sed or bash: need to go through a text file using a for next loop, replacing substrings in the file that consist of a potentially multi... (3 Replies)
Discussion started by: wind
3 Replies

8. Shell Programming and Scripting

Nested search in a file and replace the inner search

Hi Team, I am new to unix, please help me in this. I have a file named properties. The content of the file is : ##Mobile props east.url=https://qa.east.corp.com/prop/end west.url=https://qa.west.corp.com/prop/end south.url=https://qa.south.corp.com/prop/end... (2 Replies)
Discussion started by: tolearn
2 Replies

9. Shell Programming and Scripting

Speeding up substitutions

Hi all, I have a lookup table from which I am looking up values (from col1) and replacing them by corresponding values (from col2) in another file. lookup file a,b c,d So just replace a by b, and replace c by d. mainfile a,fvvgeggsegg,dvs a,fgeggefddddddddddg... (7 Replies)
Discussion started by: senhia83
7 Replies

10. Shell Programming and Scripting

Help speeding up script

This is my first experience writing unix script. I've created the following script. It does what I want it to do, but I need it to be a lot faster. Is there any way to speed it up? cat 'Tax_Provision_Sample.dat' | sort | while read p; do fn=`echo $p|cut -d~ -f2,4,3,8,9`; echo $p >> "$fn.txt";... (20 Replies)
Discussion started by: JohnN6
20 Replies
CG(1)																	     CG(1)

NAME
cg - Recursively grep for a pattern and store it. SYNOPSIS
cg [ -l ] | [ [ -i ] pattern [ files ] ] DESCRIPTION
cg does a search though text files (usually source code) recursively for a pattern, storing matches and displaying the output in a human- readable fashion. It is intended to give some of the functionaly of AT&T's cscope(1) tool, with the advantages of simplicity and not being language-specific. The script will colorize output if configured as such. It is typically run with a Perl regular expression to search for. The search can be made case insensitive by using the -i option. A list of files may also be specified with an additional argument after the pattern. Put the files pattern in quotes to make it be matched by Perl rather than by the shell. Running the script with no arguments will recall the results of the previous search. After the search, entries found can be edited using the vg(1) script. The -l option shows the last log made. SOME EXAMPLES
cg - alone recalls the previous search results. cg -i pattern - search the default list of files for all files matching the pattern (and case-insensitively). cg pattern '*.c' - search recursively for pattern in all *.c files. This automatically converts '*' to '.*' and '.' to '.' for you and does a Perl pattern match on all files in the tree. cg pattern *.c - search through the shell-expanded list of *.c files, so not done recursively (in other words, only the files your shell pass to the script as arguments). cg -l - show the last log made. COMMAND-LINE OPTIONS -i Do a case-insensitive search. -l Show the last log made. -p Toggle the default pager option. cg has a bulit-in pager function, which can be enabled or disabled by default (in .cgvgrc). If the default is enabled, this option disables the pager; if the default is disabled, this option enables it. -P Force the built-in pager to be disabled. FILES
${HOME}/.cglast Log file of the last search. ${HOME}/.cgvgrc Per-user configuration file (if the defaults are not desireable). ${HOME}/.cgvg/* Log files in $HOSTNAME.shell_pid form with the log of the last search. SEE ALSO
vg(1), perl(1), find(1), grep(1), cscope(1) AUTHOR
cg was written by Joshua Uziel <uzi@uzix.org>. 13 Mar 2002 CG(1)
All times are GMT -4. The time now is 02:36 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy