When I install Ubuntu on my BBB using Mac OS,

When I install Ubuntu on my BBB using Mac OS, how can I execute ./setup_sdcard.sh ?
I watched this docuement “http://elinux.org/BeagleBoardUbuntu#Raring_13.04_armhf” but I can’t execute " "
" setup_sdcaard.sh " on Mac OS.
just using “mktemp” but I don’t know how to using it.