So I summarize some steps:
Mac OS : Mountain Lion
Virtual Box: 4.1.20
Ubuntu: 12.04
1. setup the share folder in the Mac OS.
Choose in the VirtualBox's men: settings -> Shared Folders.
2. Add the new shared folder button
Choose the Folder Path e.g /User/reg/xxxx
and You should give the name for it, which will be used in the mount in the Ubuntu
Select Make permanent - if you would like to persist this shared folder definition
3.Now work in the Ubuntu in the Virtual Box
a. Create the folder to be shared folder mount the Mac OS Shared folder.
e.g ~/share
b. get you id
id
c. Mount the shared folder
sudo mount -t vboxsf -o uid=USER_ID Mac_OS_Shared_Folder_Name Ubuntu_Shared_Name
e.g.
sudo mount -t vboxsf -o uid=1000 share ~/share
IF you meant any issues about vboxsf
e.g.
mount.xboxsf failed no such device
make sure you installed the Virtual Box's Guest Additions
The steps about install Guest Additions
Choose the Virtual Box VM
Devices ----> Install Guest Additions
Now the Virtual Box will help you install it,
if not, you can enter the directory in the Ubuntu /media/VBOXADDITIONS_xxx
run the VBoxLinuxAdditions.run
Now make sure the vboxsf module is right
No error to run the modprobe vboxsf
4. Now you can use the shared folder.
Others about the UNP
if you run the ./daytimecocli 127.0.0.1
connect error: Connection refused
you May not start the daytime server
1. Install the xinetd
apt-get install xinetd
2. modify the /etc/xinetd.d/daytime,
change the two disable yes -------> disable no
3. Now you can /etc/init.d/daytime restart
