Virtualbox shared folder

Problem: I have to use a virtual machine running Slackware32 to test build the scripts I maintain at SlackBuilds.org. Therefore I need an easy way to transfer the scripts and other files between the host and guest machines.
Solution: I use VirtualBox installed from the All distributions AMD64 binary. The host is running pure Slackware64 and the guest additions are installed in the Slackware32 guest. So:

– Create a shared folder, following the instructions from the virtualbox forums. I keep my virtual machines on a dedicated partition mounted at /vbox, so let’s create the shared folder there: /vbox/vshare.

– In the host, specify /vbox/vshare from Settings > Shared Folders:

– I also double clicked on the entry and checked the Auto-mount and Make Permanent boxes.
– Fire up the virtual machine and create the shared folder, say just in the top of the root tree: /vshare. To make it mount on boot, add the following in /etc/rc.d/rc.local of the guest. I put just below the vboxadd, vboxadd-service and vboxadd-x11 guest additions services.

#!/bin/sh
#
# /etc/rc.d/rc.local:  Local system initialization script.
#
# Put any local startup commands in here.  Also, if you have
# anything that needs to be run at shutdown time you can
# make an /etc/rc.d/rc.local_shutdown script and put those
# commands in there.

# Start vboxadd
# If you do not wish this to be executed here then comment it out,
# and the installer will skip it next time.
if [ -x /etc/rc.d/rc.vboxadd ]; then
    /etc/rc.d/rc.vboxadd start
fi

# Start vboxadd-service
# If you do not wish this to be executed here then comment it out,
# and the installer will skip it next time.
if [ -x /etc/rc.d/rc.vboxadd-service ]; then
    /etc/rc.d/rc.vboxadd-service start
fi

# Start vboxadd-x11
# If you do not wish this to be executed here then comment it out,
# and the installer will skip it next time.
if [ -x /etc/rc.d/rc.vboxadd-x11 ]; then
    /etc/rc.d/rc.vboxadd-x11 start
fi

# Mount the shared folder
mount -t vboxsf -o uid=1000,gid=1000 vshare /vshare

Reboot and it should work. That’s it!

EDIT (14 June 2015): I made the rc.local example more clear, by pasting the contents of the whole file.