I removed my superdrive a while back but now I want to install a linux partition on my macbook. I installed rEFInd as my boot manager but now I need to boot into the arch linux iso. Normally I would just burn it to a disk and boot... but I dont have a cd drive... so can I clone the iso to my hdd so I can boot off of it?
Why not use a bootable USB stick. On the arch-linux wiki there is a tutorial about how to create a bootable USB stick (live USB stick) for OS X:
Taken from the Arch Linux Wiki: https://wiki.archlinux.org/index.php/USB_Installation_Media
On Mac OS X
To be able to use dd on your usb device on a Mac you have to do some special maneuvers. First of all insert your usb device, OS X will automount it, and run
in Terminal.app. Figure out what your usb device is called - mine was called /dev/disk1. (Just use the
mount command or
sudo dmesg | tail.) Now you run
diskutil unmountDisk /dev/disk1
to unmount the partitions on the device (i.e., /dev/disk1s1) while keeping the device proper (i.e., /dev/disk1). Now we can continue in accordance with the Linux instructions above (but use bs=8192 if you are using the OS X dd, the number comes from 1024*8).
dd if=image.iso of=/dev/disk1 bs=8192 20480+0 records in
20480+0 records out 167772160 bytes transferred in 220.016918 secs (762542 bytes/sec)
it is probably a good idea to eject your drive before physical removal at this point.
diskutil eject /dev/disk1
Creating the bootable USB drive: Overwrite the USB drive Warning: This will irrevocably destroy all data on /dev/sdx. Note: This method does not work with UEFI boot. Note: Check with lsblk that the USB device is not mounted, and use /dev/sdx instead of /dev/sdx1. These are very common mistakes!
dd bs=4M if=/path/to/archlinux.iso of=/dev/sdx
Note: Some older firmware does not understand the isohybrid hack where start of fake partition offset is 0. See https://bugs.archlinux.org/task/32189 for a fix involving isohybrid.pl.
How to restore the USB drive Because the ISO image is a hybrid which can either be burned to a disc or directly written to a USB drive, it doesn't include a standard partition table. After you install Arch Linux and you're done with the USB drive, you should zero out its first 512 bytes (meaning the boot code from the MBR and the non-standard partition table) if you want to restore it to full capacity:
dd count=1 bs=512 if=/dev/zero of=/dev/sdx
Then create a new partition table (e.g. "msdos") and filesystem (e.g. EXT4, FAT32) using gparted, or from a terminal: For EXT2/3/4 (adjust accordingly), it would be:
e2label /dev/sdx1 USB_STICK
For FAT32, install the dosfstools package and run:
mkfs.vfat -F32 /dev/sdx1
dosfslabel /dev/sdx1 USB_STICK
On the wiki there is some more information, for example if you would like to create a boot USB stick from a Windows environment.