##file operation## delete tmp bakup files under windows(file name end with '~') add extension name to all file under dir .

add_extension_name.pl

#! usr/bin/perl

@files = <*>;
if (!$_[0]) {
    $extension = '.png';
} else {
    $extension = $_[0];
}

foreach $file (@files) {
    print $file;
    if (not $file =~ /\./) {
        $newfile = $file . $extension;
        rename $file, $newfile;
    }
    print " ".$newfile."\n";
}

del_bak_files.pl

#!/usr/bin/perl

use File::Find;
use Cwd;

$path = getcwd;

find(\&wanted, $path);

sub wanted {
    if ($File::Find::name =~ /.+~$/) {
        print "we will delete the backfile \"$File::Find::name\" \n";
        unlink $File::Find::name;
    }
}