Finding files that use the most disk space

With standard available tools:

To list the top 10 largest files from the current directory: du . | sort -nr | head -n10

To list the largest directories from the current directory: du -s * | sort -nr | head -n10

UPDATE These days I usually use a more readable form (as Jay Chakra explains in another answer and leave off the | head -n10, simply let it scroll off the screen. The last line has the largest file or directory (tree).

Sometimes, eg. when you have lots of mount points in the current directory, instead of using -x or multiple --exclude=PATTERN, it is handier to mount the filesystem on an unused mount point (often /mnt) and work from there.

Mind you that when working with large (NFS) volumes, you can cause a substantial load on the storage backend (filer) when running du over lots of (sub)directories. In that case it is better to consider setting quota on the volume.

Adding to jippie's answer

To list the largest directories from the current directory in human readable format:

du -sh * | sort -hr | head -n10

Sample:

[~]$ du -sh * | sort -hr | head -n10
48M app
11M lib
6.7M    Vendor
1.1M    composer.phar
488K    phpcs.phar
488K    phpcbf.phar
72K doc
16K nbproject
8.0K    composer.lock
4.0K    README.md

It makes it more convenient to read :)

Try ncdu, as it can give you an overview of disk usage. From its website:

A disk usage analyzer with an ncurses interface, aimed to be run on a remote server where you don't have an entire gaphical setup, but have to do with a simple SSH connection. ncdu aims to be fast, simple and easy to use, and should be able to run in any minimal POSIX-like environment with ncurses installed.