Live USB

The steps to create a bootable USB containing the Arch Linux ISO.

Download the ISO

Download the ISO file from https://archlinux.org/download/.

Note: the BitTorrent Download is the recommended option and the file will look like this archlinux-version-x86_64.iso.torrent.

USB Drive Name

Find out the name of your USB drive:

ls -l /dev/disk/by-id/usb-*

To make sure it is not mounted, run lsblk and search for the MOUNTPOINTS column, you should see an empty space:

lsblk

Write the ISO

Write the ISO to the USB drive using pv:

sudo pv path/to/archlinux-version-x86_64.iso -Yo /dev/disk/by-id/usb-My_flash_drive-0:0

Note: the USB drive name should look something like /dev/disk/by-id/usb-SanDisk_Cruzer_Blade_4C530000100920118104-0:0.
Make sure to not append any partition number like My_flash_drive-0:0-part1.

For more information about this topic, check the Arch Linux wiki