The root of my disk is showing 222 MB and rest others are in GBs. See:
df -h
Filesystem Size Used Avail Use% Mounted on
udev 14G 0 14G 0% /dev
tmpfs 2.8G 174M 2.6G 7% /run
/dev/sda1 83G 78G 222M 100% /
tmpfs 14G 25M 14G 1% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 14G 0 14G 0% /sys/fs/cgroup
tmpfs 2.8G 92K 2.8G 1% /run/user/1000
How can I increase the size of /dev/sda1 while I am still in the system?