It depends, sometimes it's even switchable, e.g. take df. $ df -k / Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda3 1517

It depends, sometimes it's even switchable, e.g. take df. $ df -k / Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda3 151798672 47602008 102615608 32% / $ df -h / Filesystem Size Used Avail Use% Mounted on /dev/sda3 145G 46G 98G 32% / $ df -H / Filesystem Size Used Avail Use% Mounted on /dev/sda3 156G 49G 106G 32% / (-h "human readable" with powers of 2^10, -H "human readable" with powers of 10^3) $ df --version df (GNU coreutils) 8.22 ls has -h/--si/-k ... $ ls -h -l /proc/kcore -r-------- 1 root root 128T Apr 6 19:02 /proc/kcore $ ls --si -l /proc/kcore -r-------- 1 root root 141T Apr 6 19:03 /proc/kcore (/proc/kcore is 2^47 = 140737488355328 = 128 * 2^40 = 128 TiBi bytes)