$| = 1; # it's important for autoflush to be on
my $counter;
for ( $counter = 0; $counter < 5000; $counter++ )
{
    # ...

    # check, is this the 5th object?
    if ( ( $counter % 5 ) == 0 )
    {
        printf( "%5d\r", $counter );
    }
}
# clear status
print( ( " " x 5 ) . "\n" );