Command (Physical memory):
$ sysctl hw.physmem
Result:
hw.physmem: 108580864
Command (Free disk space in human readable format):
$ df -h
Result:
Filesystem Size Used Avail Capacity Mounted on
/dev/ada0p2 9.2G 1.7G 6.8G 20% /
devfs 1.0K 1.0K 0B 100% /dev