$dirtoget="/tsi/hadrien/deldjoo/Desktop/Ads/Sony_Serie_E_BALADEURS_Multimedia"; 
opendir(IMD, $dirtoget) || die("Cannot open directory"); 
@thefiles= readdir(IMD); 
closedir(IMD);  
 
$Fs=16000;            # [Hz] 
foreach $file (@thefiles){ 
 
	if ($file=~m/.+\.wav/){ # $file=~m/.+\.wma/  gives true or false dependig if $file matches the pattern /.+\.wav/ 
	$cmd="sox $file -r $Fs $file ????"    
        system($cmd); # here the command is called by the system 
	} 
       else {print "OK \n";} 
 
} 
 
 
My best, 
YAS

use strict; 
use warnings; 
my $Fs = 'Fs'; #On you own for this one! 
my $file = 'file1.wma'; 
my $cnvrt_file = $file; 
$cnvrt_file =~ s/\./_cnvrt./; 
my $cmd = "sox $file -r $Fs $file $cnvrt_file"; 
print $cmd;