Hcfyk

I can't determine exactly what file is eating up my disk.

Firstly I used df command to list my directories:

devtmpfs                 16438304        0  16438304   0% /dev

tmpfs                    16449868        0  16449868   0% /dev/shm

tmpfs                    16449868  1637676  14812192  10% /run

tmpfs                    16449868        0  16449868   0% /sys/fs/cgroup

/dev/mapper/fedora-root  51475068 38443612  10393632  79% /

tmpfs                    16449868      384  16449484   1% /tmp

/dev/sda3                  487652    66874    391082  15% /boot

/dev/mapper/fedora-home 889839636 44677452 799937840   6% /home

Then I ran du -h / | grep '[0-9,]+G'.

The problem is I get everything including other directories,
so I need to get specifically find /dev/mapper/fedora-root
but when I try du -h /dev/mapper/fedora-root | grep '[0-9,]+G' I get no results.

I need to know what's eating up 79% of directory /

How can I solve this?

My magic command in such situation is :

du -m . --max-depth=1 | sort -nr | head -20

To use this :

1. 
   cd into the top-level directory containing the files eating space. This can be / if you have no clue ;-)


2. run du -m . --max-depth=1 | sort -nr | head -20. This will list the 20 biggest subdirectories of the current directory, sorted by decreasing size.


3. 
   cd into the biggest directory and repeat the du ... command until you find the BIG file(s)

ncdu is a great tool for this kind of problem. Here's the corresponding package.

You can use -x if you want to stay on only one filesystem, without following symlinks. For example, as root:

ncdu -x /home

It's the command line equivalent of DaisyDisk, Baobab or WinDirStat.

It might take a long time to scan a large folders, but once it's done it should be very fast to find the largest files.

If you have a feel for the actual size of the file you can find files larger than a specific size.

Eg, to find files larger than 10 MiB:

find /mounted/drive -size +10M

Or

find /mounted/drive -size +10M -exec ls -lh {} +

Httqm's suggestion is also good if the problem isn't one big file but a large collection of smaller files. That is use du to show directory totals. Limiting with --max-depth is very useful with large directory trees:

du -m some/directory --max-depth=1 | sort -nr | head -20

du some/directory --max-depth=1 | sort -n | tail -21

Will break a single directory down into sub-directories, the second of these gives you the total for the directory you're listing as well.

Use this command to find out which directories are the largest:

du -a / | sort -n -r | head