while (condition)    #condition ~ 1, loop basically forever
{
 opendir(MYDIR, $dirname);
 my @mail = grep { $_ ne '.' and $_ ne '..' } readdir MYDIR;
 
 foreach (@mail) {
    # do stuff
    # delete each file
 }
 
 undef(@mail);                  # @mail shuld be empty now
 closedir(MYDIR);
 sleep(1);                      # give cpu a break   

}
# more stuff...