What is the easiest way to free space on a hard drive?

"I played with cron once so it may have consumed my mass memory, but really I have no clue." No clue, you say? never would have guessed. :)

su -
cd /
du -s ./* | sort -n

• du shows disk usage, in blocks (1 block = 0.5 kilobytes, in all cases that matter to you.)

• -s means, "summary", so it gives only a total for each argument "./*" being the argument.

• piping it into sort -n means sort numerically. The larger numbers at the bottom.

• So, you'll get a list of directories with the ones using the most space at the bottom.

If that's not enough help, say you get:

60380   ./root
142468  ./etc
537716  ./var
627264  ./lib
5757600 ./usr
28859472        ./home

• and you see that ./home is the biggest piggy, ok, cd into /home, and do the same du -s | sort -n. Then you see who in /home is taking up space. (on a single user system, well, it's probably you.)

• Then cd into there, and do du -s | sort -n again.

Keep doing this until you find the culprit. When you find the culprit, you may say, oh yeah... that's my collection of hi-res renderings of Romulan Birds of Prey for my star trek RPG game that I'm building, so yeah, of course that takes up a lot of space, or you may say, of course that takes up a lot of space, so let's rm -fr that bad boy.

Magic words to remember:

du -s | sort -n

KDirStat is another option which will help you identify large files and directories.

I've used the Windows clone WinDirStat a lot and it is an awesome tool.

Linux tool ncdu is very convenient in my opinion. It's like interactive du.

Some features

• Text interface (ncurses); works via SSH, no Xserver needed.
• Still you can move within directory tree to find large dirs/files quickly.
• You can delete dir/file from within the program.

Screenshot

Well, kind of. There's no point in pasting picture, text will be enough:

ncdu 1.10 ~ Use the arrow keys to navigate, press ? for help                    
--- / --------------------------------------------------------------------------
    6,7GiB [##########] /usr
    3,4GiB [#####     ] /var
  553,1MiB [          ] /lib
  529,1MiB [          ] /opt
   35,1MiB [          ] /etc
   32,5MiB [          ] /home_old                                               
   16,4MiB [          ] /sbin
    9,9MiB [          ] /bin
    8,2MiB┌───ncdu help─────────────────1:Keys───2:Format───3:About──┐
    3,8MiB│                                                          │
    1,3MiB│       up, k  Move cursor up                              │
  500,0KiB│     down, j  Move cursor down                            │
  124,0KiB│ right/enter  Open selected directory                     │
   12,0KiB│  left, <, h  Open parent directory                       │
    8,0KiB│           n  Sort by name (ascending/descending)         │
@   4,0KiB│           s  Sort by size (ascending/descending)         │
@   4,0KiB│           C  Sort by items (ascending/descending)        │
@   4,0KiB│           d  Delete selected file or directory           │
    0,0  B│           t  Toggle dirs before files when sorting       │
>   0,0  B│           g  Show percentage and/or graph                │
e   0,0  B│                        -- more --                        │
>   0,0  B│                                     Press q to continue  │
>   0,0  B└──────────────────────────────────────────────────────────┘
>   0,0  B [          ] /home
>   0,0  B [          ] /dev
e   0,0  B [          ] /cpusets
e   0,0  B [          ] /cdrom
>   0,0  B [          ] /boot



 Total disk usage:  11,3GiB  Apparent size:  11,1GiB  Items: 289029             

Usage:

ncdu -x /foo/bar/mountpoint

Use sudo (and caution!) when necessary. The -x option is important, it makes ncdu stay within single filesystem (du has the same option). In the example (above) my /home is on a different partition than / where ncdu started, therefore it does not count – thanks to -x switch exactly.