df -h

df -h is a simple command you can use to find out how much free space you have in your linux hard drive. with this command you can find out and display the space available in your file system. it will also show you some important information

you can also try this command:
du -hs /

this is the command i use most often, it shows me how much spache each directory is using.

for example;
du -h --max-depth=1 /