/dev/urandom

wikipedia:urandom

 head -10 /dev/urandom | sha512sum | cut -b 1-30

https://github.com/coreutils/coreutils/blob/master/NEWS

 shred, sort, shuf: now use an internal pseudorandom generator by default.
 This is mainly noticeable in shred where the 3 random passes it does by
 default should proceed at the speed of the disk.  Previously /dev/urandom
 was used if available, which is relatively slow on GNU/Linux systems.

See also

• Random, /dev/urandom
• oathtool
• Linux Kernel: namespaces, Cgroups, OOM, proc, Linux Kernel changelog, sysctl, userfaultfd, Grub, ENOSPC, ENOMEM, DKMS, syscall, Transparent huge pages, smatch, sysfs, vm.swappiness, CFS, Runlevel, Jens Axboe, Consistent Network Device Naming, Initial ramdisk (initrd), modprobe, MTD, Linux Kernel vulnerabilities, /sys/kernel/, KernelCare, unix://, Data Plane Development Kit (DPDK)