$ mkdir tmp

$ ls -ld tmp/
drwxr-xr-x 2 mario mario 4096 Sep 21 17:20 tmp/

$ for i in `seq 1000`; do touch tmp/$i; done

$ ls -ld tmp/
drwxr-xr-x 2 mario mario 20480 Sep 21 17:21 tmp/

$ rm tmp/*

$ ls -ld tmp/
drwxr-xr-x 2 mario mario 20480 Sep 21 17:21 tmp/