use File::Copy;
use strict;

my($sourcedir) = shift || die "No source dir";
opendir(DIR,"$sourcedir");
foreach (grep !/^\.\.?$/,readdir DIR) {
    if (/^(\S+)_(\S+)\.(\S+)$/) {
	if (move($_,"$1-$2.$3")) {
	    print "Moved $_ to $1-$2.$3\n";
	} else {
	    print "Error moving $_ to $1-$2.$3\n";
	}
    }
}