df, free

df

• file system disk space usage

$ df
Filesystem     1K-blocks     Used Available Use% Mounted on
udev             1892524        0   1892524   0% /dev
tmpfs             388436     4040    384396   2% /run
/dev/mmcblk0p2  61245952 10903412  47810480  19% /

free

• Display amount of free and used memory in the system

$ free
              total        used        free      shared  buff/cache   available
Mem:        3884332      352648     2717492        4056      814192     3477524
Swap:             0           0           0