Find the largest subdirectories
The free space on your HDD is low. Which directories are the largest? What consumes so much space?
ncdu“, which stands for NCurses Disk Usage.
“ncdu (NCurses Disk Usage) is a curses-based version of the well-known ‘du’, and provides a fast way to see what directories are using your disk space.” (source: man)
For a command line solution, check out this post: How Do I Find The Largest Top 10 Files and Directories On a Linux / UNIX / BSD?