my $watchlog = '/tmp/watchlog.txt';

    printLog("Watch file: $watchlog\n"); #Whatever and wherever you want to print


sub printLog { 
my $info = shift @_;

    open (LOG, '>>:encoding(utf8)', $watchlog) or die "Cannot open the logfile. $!\n";
    print LOG $info;
    close LOG;

} #END SUB printLog