Shell script to create RamDisk and move temp folders to RamDisk. Increased original RamFS values from 256/64 to 512/128. Moved startup item to /Library/StartupItems instead of /System/Library/StartupItems. https://developer.apple.com/library/mac/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/StartupItems.html

MoveTemporaryFoldersToRamdisk_MacOSX.sh

#!/bin/bash

# +----------------------------------------------------------------------+
# |                                                                      |
# |  Set up Mac OS X to store temporary files in RAM rather than on disk.|
# |                                                                      |
# |  By Philipp Klaus <http://blog.philippklaus.de>                      |
# |                                                                      |
# |  Originally by Ricardo Gameiro <http://blogs.nullvision.com/?p=357>  |
# |  Changes by Daniel Jenkins                                           |
# |     <http://blogs.nullvision.com/?p=357#comment-1140>                |
# |  Additional changes by Benjamin Chu <http://intechnicolor.net>       |
# +----------------------------------------------------------------------+

# cd /System/Library/StartupItems
# Startup Items in /System/Library/StartupItems is deprecated
cd /Library/StartupItems
sudo mkdir RamFS
sudo chown -R root:wheel RamFS
sudo chmod -R u+rwX,g+rX,o+rX RamFS
cat << "EOF" | sudo tee RamFS/RamFS > /dev/null
#!/bin/sh
# Create a RAM disk with same perms as mountpoint

RAMDisk() {
    mntpt=$1
    rdsize=$(($2*1024*1024/512))
    echo "Creating RamFS for $mntpt"
    # Create the RAM disk.
    dev=`hdik -drivekey system-image=yes -nomount ram://$rdsize`
    # Successfull creation...
    if [ $? -eq 0 ] ; then
        # Create HFS on the RAM volume.
        newfs_hfs $dev
        # Store permissions from old mount point.
        eval `/usr/bin/stat -s $mntpt`
        # Mount the RAM disk to the target mount point.
        mount -t hfs -o union -o nobrowse $dev $mntpt
        # Restore permissions like they were on old volume.
        chown $st_uid:$st_gid $mntpt
        chmod $st_mode $mntpt
    fi
}

# Test for arguments.
if [ -z $1 ]; then
    echo "Usage: $0 [start|stop|restart] "
    exit 1
fi

# Source the common setup functions for startup scripts
test -r /etc/rc.common || exit 1 
. /etc/rc.common

StartService () {
    ConsoleMessage "Starting RamFS disks..."
    # Change values here to allocate more RAM
    RAMDisk /private/tmp 512
    RAMDisk /var/run 128
    #RAMDisk /var/db 1024
    #mkdir -m 1777 /var/db/mds
}
StopService () {
    ConsoleMessage "Stopping RamFS disks, nothing will be done here..."
    # diskutil unmount /private/tmp /private/var/run
    # diskutil unmount /private/var/run
}

RestartService () {
    ConsoleMessage "Restarting RamFS disks, nothing will be done here..."
}

RunService "$1"
EOF
sudo chmod u+x,g+x,o+x RamFS/RamFS


cat << EOF | sudo tee RamFS/StartupParameters.plist > /dev/null
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist SYSTEM "file://localhost/System/Library/DTDs/PropertyList.dtd">
<plist version="0.9">
    <dict>
        <key>Description</key>
        <string>RamFS Disks Manager</string>
        <key>OrderPreference</key>
        <string>Early</string>
        <key>Provides</key>
        <array>
                <string>RamFS</string>
        </array>
        <key>Uses</key>
        <array>
                <string>Disks</string>
        </array>
    </dict>
</plist>
EOF