To be able to do a grep on a file via a perl script do you have to read the whole file in before performing the search and replace? I've been hearing that reading the whole file in takes up memory and if multiple users are running the script then you better have alot of swap and memory.
Is this correct? If this is the case how else could I do a grep to do a search and replace without using all the resources? On Wed, 24 Nov 2004 07:00:24 -0500, FlashMX wrote: > >Could you give an example of using grep on a array to do a replace? > > >On Wed, 24 Nov 2004 10:05:39 +0530, Prasanna Kothari wrote: > >>Hi, >>Replace >>$output = ~ s/AAA*?BBBt/AAA 111 *?222 BBB/g; >>with >>my $output =~ s/AAA*?BBBt/AAA 111 *?222 BBB/g; >> >>You can use "perl -c <filename>" which will show you such type of errors. >> >>After opening the output file, it's better to check if the file is >>opened successfully(as done in the case of INPUT). >> >>I think there's something wrong with the logic. >>The INPUT file is opened, all it's contents are in the array >>@match_lines, and then after doing a pattern match, you are just >>printing the values to the output file. >>Your script has not replaced anything. >>Use grep function to replace all the contents of an array and write the >>array back to the output file. >> >> >>--Prasanna >>FlashMX wrote: >> >>>Hi, >>> >>>The code below opens a file and writes the contents to a temporary file. I >>>need to do a search and replace of certain matches in the files and I >>>thought I might be able to use regular >>>expressions. >>>Being new to perl and now trying expressions has almost put me over the edge. >>> >>>When I run the below code I get this error: >>> >>>Global symbol “output” requires explicit package name at filename.pl line >>>18.... >>> >>>I’m not sure whats wrong by the error. >>> >>>#!/usr/local/bin/perl >>>use strict ; >>> >>>my $ofile = "file.out"; >>>my $ifile = "file.in"; >>> >>>open(INPUT, $ifile) or die "Can't open input file: $ifile ($!)" ; >>> my @match_lines = <INPUT>; >>>close ( INPUT ); >>> >>> >>>open( OUTPUT, "> $ofile" ); >>> >>> $output = ~ s/AAA*?BBBt/AAA 111 *?222 BBB/g; >>> >>> print OUTPUT @match_lines; >>>close ( OUTPUT ); >>> >>>#rename($ofile, $ifile) ; >>> >>> >>> >>> >>> >>> >>> >> >> >>-- >>To unsubscribe, e-mail: [EMAIL PROTECTED] >>For additional commands, e-mail: [EMAIL PROTECTED] >><http://learn.perl.org/> <http://learn.perl.org/first-response> >> >> > > > > >-- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] ><http://learn.perl.org/> <http://learn.perl.org/first-response> > > -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
