To see the amount of free disk space, you can use the df command in Linux.
# Shows the amount of free disk space
df
Once you execute the df command on the terminal in Linux, you can see an output like below,

From the above output you can see the:
Usedspace on a particular diskAvailablespace on a particular disk- and 
Capacityused on a particular disk in percentage. 
See the above code live in repl.it.
That's all 😃!