How to read a text file, extract a records that contains a string, export the result into a temporary file

tuakilan has asked for the wisdom of the Perl Monks concerning the following question:

hi all, I have a need to write a perl script to do the following

1. read a log file
2. search the logfile.txt for a specific string, in this case the stri
+ng "TWO"
3. extract record that contains the string "TWO" from log file into an
+other file
[download]

I tried this example but it does not work as what i wish

#!/usr/bin/perl -w
use strict;
use IO::File;
use constant FILE => 'b2bclient-gateway-heartbeat.log';
use constant FIND => 'production';
IO::File->input_record_separator(FIND);
my $fh = IO::File->new(FILE, O_RDONLY) or die 'Could not open file ', 
+FILE, ": $!";
$fh->getline;
#fast forward to the first match, print each occurence in the file
print IO::File->input_record_separator

while $fh->getline;
$fh->close;
[download]

====================================== The logfile.txt ooks like this ============================

2007-Nov-07 00:00:00 UTC (GMT +0000) - Poll: channel = ONE, ref =
2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = THREE, ref =
2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref =
2007-Nov-07 00:00:04 UTC (GMT +0000) - Poll: channel = TWO, ref =
[download]

Thanks - TuaKiLan tuakilan@gmail.com

Comment on How to read a text file, extract a records that contains a string, export the result into a temporary file Select or Download Code

Replies are listed 'Best First'.
Re: How to read a text file, extract a records that contains a string, export the result into a temporary file by hipowls (Curate) on Feb 14, 2008 at 09:34 UTC
Or if you're on a windows machine without grep `perl -ne'print if /TWO/' b2bclient-gateway-heartbeat.log > output.txt` If it is part of a larger task then `my $in_file = 'b2bclient-gateway-heartbeat.log'; open my $in_fh, '<', $in_file or die "Could not open file $in_file: $! +"; my $out_file = 'output.txt'; open my $out_fh, '>', $out_file or die "Could not open file $out_file: + $!"; while ( my $line = <$in_fh> ) { print {$out_fh} $line if $line =~ /TWO/; } close $in_fh or die "Could not close file $in_file: $!"; close $out_fh or die "Could not close file $out_file: $!";` [download]	[reply] [d/l] [select]
Re^2: How to read a text file, extract a records that contains a string, export the result into a temporary file by tuakilan (Acolyte) on Feb 15, 2008 at 02:55 UTC
hipowls, thanks for your tip, it works for one of the tasks that i need to perform on the text file. regards - tuakilan	[reply]
Re: How to read a text file, extract a records that contains a string, export the result into a temporary file by svenXY (Deacon) on Feb 14, 2008 at 09:35 UTC
Hi, your example makes it harder as necessary... Besides, it does not actually do something. I'd assume it doesn't even compile properly. Here's a working example (opening/closing the logfile is here replaced by reading from the DATA handle): use strict; use warnings; my $infile = 'b2bclient-gateway-heartbeat.log'; my $outfile = 'results.txt'; my($fh_out, $fh); open($fh_out, '>', $outfile) or die "Could not open outfile: $!"; # open($fh, '<', $infile) or die "Could not open logfile: $!"; # while (<$fh>) { while (<DATA>) { /TWO/ && print $fh_out $_; } close $fh_out; #close $fh; __DATA__ 2007-Nov-07 00:00:00 UTC (GMT +0000) - Poll: channel = ONE, ref = 2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref = 2007-Nov-07 00:00:01 UTC (GMT +0000) - Poll: channel = TWO, ref = 2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = THREE, ref = 2007-Nov-07 00:00:02 UTC (GMT +0000) - Poll: channel = TWO, ref = 2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref = 2007-Nov-07 00:00:03 UTC (GMT +0000) - Poll: channel = TWO, ref = 2007-Nov-07 00:00:04 UTC (GMT +0000) - Poll: channel = TWO, ref = [download] Regards, svenXY	[reply] [d/l]
Re: How to read a text file, extract a records that contains a string, export the result into a temporary file by Punitha (Priest) on Feb 14, 2008 at 09:39 UTC
Hi tuakilan, try this `use strict; open(IN,'logfile.txt') or die("cannot open the log file for reading\n" +); open(OUT,'>output.txt') or die("cannot open the output file for writin +g\n");######To create the output file while(<IN>){######to read the input file print OUT "$_" if($_=~/\bTWO\b/i); } close(IN); close(OUT);` [download] Punitha	[reply] [d/l]
Re: How to read a text file, extract a records that contains a string, export the result into a temporary file by apl (Monsignor) on Feb 14, 2008 at 10:51 UTC
A minor tweak to a great solution by svenXY: `while (<STDIN>) { /TWO/ && print STDOUT $_; }` [download] By the way,you really should go to your teacher and ask for a tutor.	[reply] [d/l]
Re: How to read a text file, extract a records that contains a string, export the result into a temporary file by Anonymous Monk on Feb 14, 2008 at 09:21 UTC
`$ grep TWO logfile.txt >output.txt`	[reply] [d/l]


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