ken@titan ~/tmp/pm_11150231_dir_rand_select
$ ./rand_select_files_sample.pl
/home/ken/tmp/pm_11150231_dir_rand_select/inc2/n.x
/home/ken/tmp/pm_11150231_dir_rand_select/a.x
/home/ken/tmp/pm_11150231_dir_rand_select/c.z

ken@titan ~/tmp/pm_11150231_dir_rand_select
$ ./rand_select_files_sample.pl
/home/ken/tmp/pm_11150231_dir_rand_select/inc1/j.z
/home/ken/tmp/pm_11150231_dir_rand_select/c.z
/home/ken/tmp/pm_11150231_dir_rand_select/inc1/h.x

ken@titan ~/tmp/pm_11150231_dir_rand_select
$ ./rand_select_files_sample.pl
/home/ken/tmp/pm_11150231_dir_rand_select/inc1/j.z
/home/ken/tmp/pm_11150231_dir_rand_select/c.z
/home/ken/tmp/pm_11150231_dir_rand_select/a.x