permission denied error when reading thru set of text files at once!!!

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

Dear monks, i have a task to open a directory and read thru some 100 or 150 text files in it line by line and substitute a value for each .when i read thru half way of the 150 txt files i get a permission denied at xx.pl line xx error and the script terminates ubruptly. i even tried using flock,but no use. Please help me on this? Thanks, seeker this is my code

use File::Basename;
use Fcntl qw(:flock);

print"enter the input directory path:\n";
chomp($indir=<STDIN>);
print"enter the events directory path:\n";
chomp($evdir=<STDIN>);
print"enter the output directory name:\n";
chomp($tmpdir=<>);

if (($indir eq $outdir)||($tmpdir eq $outdir)||($indir eq $tmpdir))
{
print"you cannot have same input and ouput directory please change:\n"
+;
exit();
}
else
{

$ever="$evdir/events.txt";
chdir ("$indir") or die "$!";
opendir(DIR,".") or die "$!";
my @files=readdir DIR;

close DIR;
my %result=();
foreach $file(@files)
{
unless (($file eq ".") || ($file eq "..") )
{
$base=basename("$file",".txt");
$filein="$indir/$file";
$srtfile="$outdir/$base._events.txt";
$tmpout="$tmpdir/$base._unsortedevents.txt";
open evein,$ever or die $!;
flock(evein, LOCK_EX) or die "Cannot lock - $!";  
while (<evein>)
{
chomp;
next unless length;
my ($key,$value)=split /===/,$_;
$result{$key}=$value;
}
close(evein);
while (my($key,$value)=each (%result))
{
open fln,$filein or die $!;
flock(fln, LOCK_EX) or die "Cannot lock - $!";  
while(<fln>)
{
my ($line)=$_;
chomp($line);
if ($line=~m/$key/ig)
{
$line=~s/$key/$value/eeig;

open flow,">>$tmpout" or die $!; #prints matching log lines in events.
flock(flow,LOCK_EX) or die "Cannot lock - $!";
print flow $line,"\n";
}

}
print $value,"\n";    
close(flow);
}

}


}
print"<----------------------------------------------->\n";
print "\t\t action done\n";
print"<----------------------------------------------->\n";
print "\t\t$count results found in search\n";
print"<****************..............******************>>\n";

close $out;

}
[download]

Comment on permission denied error when reading thru set of text files at once!!! Download Code

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Re: permission denied error when reading thru set of text files at once!!! by jwkrahn (Abbot) on Mar 15, 2011 at 06:42 UTC
`print"enter the input directory path:\n"; chomp($indir=<STDIN>); print"enter the events directory path:\n"; chomp($evdir=<STDIN>); print"enter the output directory name:\n"; chomp($tmpdir=<>);` [download] Why do you use `<STDIN>` for the first two variables and `<>` for the third? `opendir(DIR,".") or die "$!"; my @files=readdir DIR; close DIR;` [download] You have to use closedir to close a directory handle opened with opendir. `open evein,$ever or die $!; flock(evein, LOCK_EX) or die "Cannot lock - $!"; while (<evein>) { chomp; next unless length; my ($key,$value)=split /===/,$_; $result{$key}=$value; } close(evein);` [download] The value of `$ever` doesn't change inside this loop so this code should be outside the loop where `$ever` is set. `open evein,$ever or die $!;` [download] You are trying to open 'events.txt' from a directory entered by the user. If the user uses a relative path then your program won't be able to find it. You should give the user more information than just the contents of $!. `flock(evein, LOCK_EX) or die "Cannot lock - $!";` [download] You can't `LOCK_EX` a file opened only for input, only for output. `while(<fln>) { my ($line)=$_;` [download] That is usually written as: `while ( my $line = <fln> ) {` [download]	[reply] [d/l] [select]
Re^2: permission denied error when reading thru set of text files at once!!! by ikegami (Patriarch) on Mar 15, 2011 at 06:47 UTC
You can't LOCK_EX a file opened only for input, only for output. `$ perl -E' use Fcntl qw( LOCK_EX ); open(my $fh, "<", ".bashrc") or die; flock($fh, LOCK_EX) or die; say "ok"; ' ok` [download] Can't? no. But does it make sense to? Probably never.	[reply] [d/l]
Re^3: permission denied error when reading thru set of text files at once!!! (flock) by tye (Sage) on Mar 15, 2011 at 13:28 UTC
flock is implemented several different ways in different builds of Perl. Some of those ways indeed do not even allow exclusive locks against read-only file handles. - tye	[reply]
Re: permission denied error when reading thru set of text files at once!!! by GrandFather (Saint) on Mar 15, 2011 at 04:59 UTC
Just use strictures (use strict; use warnings;) and you will see that there is an error on line xx - 3 that is causing the problem. If that doesn't help (although it should, strictures always help) you may have to actually show us the code. Update: Oh, I see you made a stealth update to your node. Still, you haven't told us which line the error occurs on Update: on downloading your code and adding strictures I notice that $outdir is never initialised but is tested against. Also flow is used as a file handle for multiple files inside a while loop and the files only ever have one line written to them. flow is only closed once (regardless of whether it was opened or not) outside the while loop. $count is used in a print, but is never initialised. File handle out is closed but it is never opened or otherwise used. True laziness is hard work	[reply]
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