# Find out what takes space on the hard drive, in a Linux/Unix machine

I was struggling with a machine that was completely out of space. Here are some
ways to find what is using the most storage.

## Find out the system capacity and available disk space

Use the `df` "disk filesystem" (or "disk free") command to see how much free
space there is on the disk(s):

```shell
$ df -H
Filesystem      Size  Used Avail Use% Mounted on
udev            1.1G  8.2k  1.1G   1% /dev
tmpfs           210M  418k  210M   1% /run
/dev/vda1        32G   21G  9.0G  71% /
```

This will show all mounted filesystems. Get the usage of an individual
filesystem by referring to it by name:

```shell
$ df -H /dev/vda1
```

## Find out the size of a file

The `ls` command coupled with "the human readable", "list", and "all" flags is
great for gauging file sizes in a directory:

```shell
$ ls -lah
```

That’ll show hidden files, too.

### The du (disk use) command

The "disk use" command shows the size of a file:

```shell
$ du -h archive.zip
800M    archive.zip
```

## Find out size of a directory

Combine the `du` command with the "summarize" `-s, --summarize` flag to show the
size of a directory:

```shell
$ du -sh /var/www
8.9G    /var/www
```

`-s, --summarize`

Display only a total for each argument.

`-h, --human-readable`

Print sizes in human readable format (e.g., 1K 234M 2G).

The next one lists the sizes of the 10 largest directories in the current
working directory, in human readable form:

```shell
$ cd /var/www
$ du -hsx * | sort -rh | head -10
```

[Source](https://www.cyberciti.biz/faq/how-do-i-find-the-largest-filesdirectories-on-a-linuxunixbsd-filesystem/)

## Find packages that take a lot of space

In Debian systems you can use the `aptitude` command to sort by `installsize`,
and then pipe it to the `tail` command to get a reasonable amount of results.
This churns out the packages in ascending order:

```shell
$ aptitude search "~i" --display-format "%p %I" --sort installsize | tail -10
linux-headers-3.8.0-29                    60.1 MB
libwireshark3                             62.9 MB
linux-headers-3.13.0-51                   63.4 MB
linux-headers-3.13.0-161                  63.6 MB
libwireshark11                            83.9 MB
linux-firmware                             127 MB
linux-image-extra-3.13.0-51-generic       152 MB
linux-image-extra-3.13.0-161-generic      155 MB
linux-image-3.8.0-29-generic              176 MB
mongodb-org-tools                         238 MB
```

Tweak the number in `tail` to get more results.

## Check for MySQL databases

Maybe there’s a bloated database using the lion’s share of the space. Log in to
the MySQL prompt to check:

```shell
$ mysql -u root -p
```

See if you have too many databases, or something like that:

```sql
SHOW DATABASES;
```

Or
[get a database size](https://stackoverflow.com/questions/1733507/how-to-get-size-of-mysql-database)
in human readable form:

```sql
SELECT table_schema AS "db_name", SUM(data_length + index_length) / 1024 / 1024 / 1024 AS "Size (GB)" FROM information_schema.TABLES GROUP BY table_schema
```

I’ve got a [post with simple MySQL operations](/mysql-command-cheat-sheet), if
you’re interested.

## Check the size of logs

Just to be sure that logs haven’t bloated out of control for some reason, the
`/var/log` can be checked:

```shell
$ du -sh /var/log
629M    /var/log
```