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

Hello Monks! I am trying to change the file extension of all files with .txt to .html. I am using windows. Here is what I have so far. It runs fine without errors but doesnt provide the expected result. Could you please help? Thanks! 

#!/usr/local/bin/perl

use strict;
use warnings;
use File::Copy;


my $directory = 'C:\Perl';

chdir($directory) or die "Can't chdir to $directory $!"; 
opendir(DIR, $directory) || die "Couldn't opendir: $!\n";  

my @filesWithSpaces = grep(/.*\s.*\..*/, readdir (DIR));  

foreach (@filesWithSpaces)
{   
my $newName = $_;   
$newName =~ s/html$/txt/g;   
print "RENAMING: $_ -> $newName \n";   
rename($_, $newName); 
}

closedir(DIR);

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Sorry I did some more troubleshooting and got it working. Thank you!

#!/usr/local/bin/perl

use strict;
use warnings;
use File::Copy;


my $directory = 'C:\Perl';

chdir($directory) or die "Can't chdir to $directory $!"; 
opendir(DIR, $directory) || die "Couldn't opendir: $!\n";  

my @files = grep { $_ ne '.' && $_ ne '..' } readdir DIR; 

foreach(@files)
{   
print $_,"\n";
my $newName = $_;   
$newName =~ s/html$/txt/g;   
print "RENAMING: $_ -> $newName \n";   
rename($_, $newName); 
}

closedir(DIR);

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Replies are listed 'Best First'.
Re: Changing file extensions
by wind (Priest) on May 05, 2011 at 23:14 UTC
    You're regex appears to be inverted if you want to change .txt to .html. Also, a global modifier is not necessary. 
    $newName =~ s/html$/txt/g;

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    The following would probably get you what you want: 
    use strict;
use warnings;

my $directory = 'C:\Perl';

chdir($directory) or die "Can't chdir to $directory $!"; 

opendir my $dh, $directory or die "Couldn't opendir: $!\n";
foreach (readdir $dh) {
    next if /^\.+$/;
    if ((my $html = $_) =~ s/txt$/html/) {
        rename($_, $html) or die "Can't rename: $!";
    }
}
closedir $dh;

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Re: Changing file extensions
by BrowserUk (Patriarch) on May 05, 2011 at 23:57 UTC

    Why not: 

    system 'ren *.txt *.html';

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    Or just type it on the command line.

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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Re: Changing file extensions
by tchrist (Pilgrim) on May 05, 2011 at 23:33 UTC
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      Speaking of shell command, it's way simpler than that: 
      >rename *.txt *.html

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      aka 
      >ren *.txt *.html

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Re: Changing file extensions
by John M. Dlugosz (Monsignor) on May 06, 2011 at 07:24 UTC
    Wouldn't it be simpler just to use the shell? rename *.txt *.html.
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