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


##</code><code>##


 my @mail = grep { $_ ne '.' and $_ ne '..' } readdir INDIR;

##</code><code>##

 my @mail = grep { $_ ne '.' and $_ ne '..' } readdir MYDIR;