What is eating up my disk space?

Question

I have very recently installed Ubuntu 15.10. I have been watching the available amount of memory over two days, and i noticed that the free memory goes on decreasing at a slow rate. Initially the used memory was 5GB, Then it went on increasing to 6 to 6.5 and now it stands around 6.8. I haven't installed anything significant over this period (except some small packages worth a few MBs) .My home folder is just few 100kbs. What is eating up my disk space? How can find out if something is going on?

Answer 1

The indicated amount seems to be .deb cache in majority. Issue this command:

sudo apt-get clean

and after that check again the disk usage.

Answer 2

You can find out how much space sub-directories occupy using the following command:

sudo du -hxd 1 YOUR_PATH 2>/dev/null | sort -hr

What it does:

• sudo: run the du command as root - only needed/recommended if you want to list stuff outside your own home directory.
• du: disk usage analyzing tool. Arguments:
  • -h: use human readable numeric output (i.e. 2048 bytes = 2K)
  • -x: stay on the same file system, do not list directories which are just mounted there
  • -d 1: display recursion depth is set to 1, that means it will only print the given directory and the direct subdirectories.
  • YOUR_PATH: The path which should be analyzed. Change this to whatever path you want.
  • 2>/dev/null: we do not want error output (e.g. from when it tries to get the size of virtual files), so we pipe that to the digital nirvana a.k.a. /dev/null.
• |: use the output of the previous command as input for the next command
• sort: sort the input. Arguments:
  • -h: recognize numbers like 2K and sort them according to their real value
  • -r: reversed order: print the largest numbers first

Example for my file system root /:

$ sudo du -hxd 1 / 2>/dev/null | sort -hr
5,7G    /
4,0G    /usr
1,3G    /var
358M    /lib
49M     /opt
15M     /etc
13M     /sbin
13M     /bin
840K    /tmp
32K     /root
16K     /lost+found
8,0K    /media
4,0K    /srv
4,0K    /mnt
4,0K    /lib64
4,0K    /cdrom

Note that the given directory's total size is also included, not only the subdirectories.