Where Online Learning is simpler!

The output of your command "$ df -F tmpfs" is:

Filesystem     1K-blocks  Used Available Use% Mounted on
tmpfs           12182508   252  12182256   1% /dev/shm
tmpfs            2436504  4840   2431664   1% /run
tmpfs               5120     8      5112   1% /run/lock
tmpfs            2436500   112   2436388   1% /run/user/131
tmpfs            2436500    96   2436404   1% /run/user/1000