use CWD;
my $org_dir = cwd;

chdir($desired_dir) || die "can't cd: $!";
opendir(DIR, $desired_dir) || die "can't opendir: $!";

while(my $file = readdir DIR){
   next if -d $file;
   # preform operations below on $file 
}
closedir DIR;

chdir($org_dir) || die "can't get back to $org_dir: $!";