$ mkdir -m 666 dir
$ echo hallo > dir/hallo
bash: dir/hallo: Permission denied
$ ll
total 0
drw-rw-rw-  2 pepe users 40 Jun  9 19:29 dir/
$ chmod 777 dir
$ echo hallo > dir/hallo
$ chmod 666 dir
$ ls dir
hallo
$ ls -l dir
ls: dir/hallo: Permission denied
total 0
$ cat dir/hallo
cat: dir/hallo: Permission denied
$ rm dir/hallo 
rm: cannot lstat `dir/hallo': Permission denied