In Linux, the df command is used to check disk space available on an individual device. But if you will use the df command without any parameter, it will show you used and available disk space in bytes. For better readability, to check the disk space in MB (Megabyte) and in GB (Gigabyte) form, use -h option. Below is an example:
Linux - Check Disk Space in Bytes
$ df
Output
Filesystem 1K-blocks Used Available Use% Mounted on
udev 1012760 0 1012760 0% /dev
tmpfs 206252 3740 202512 2% /run
/dev/sda1 29799484 4494956 23767760 16% /
tmpfs 1031244 172 1031072 1% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 1031244 0 1031244 0% /sys/fs/cgroup
linux 479230972 85128384 394102588 18% /media/sf_linux
ubuntu 479230972 85128384 394102588 18% /media/sf_ubuntu
tmpfs 206252 56 206196 1% /run/user/1000
/dev/sr0 57064 57064 0 100% /media/vin/VBox_GAs_5.2.26
Linux - Check Disk Space in MB (Megabyte), GB (Gigabyte) Form
$ df -h
Output
Filesystem Size Used Avail Use% Mounted on
udev 990M 0 990M 0% /dev
tmpfs 202M 3.7M 198M 2% /run
/dev/sda1 29G 4.3G 23G 16% /
tmpfs 1008M 172K 1007M 1% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 1008M 0 1008M 0% /sys/fs/cgroup
linux 458G 82G 376G 18% /media/sf_linux
ubuntu 458G 82G 376G 18% /media/sf_ubuntu
tmpfs 202M 56K 202M 1% /run/user/1000
/dev/sr0 56M 56M 0 100% /media/vin/VBox_GAs_5.2.26
Now instead of big block numbers, the disk sizes are displayed in a human readable form in MB and GB form.