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Disk Space and Usage

It is often useful to know how much disk space you have left available, and how much space your various files and directories are taking up. To find out how much disk space is free, use the df command:

[phasnip@mijpnb1 Linux]$ df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/hda5              2008108   1364996    541104  72% /
none                    127764         0    127764   0% /dev/shm
/dev/hda7              1818352   1223956    502024  71% /home
/dev/hda1              6644480   5266840   1377640  80% /mnt/windows
/dev/hda8               806368    542784    222620  71% /usr/local

This tells you how much space is free on each storage device in the computer. The first column is the device (every device in the computer has a special file in /dev), and the last column tells you the mount point for the device. The space is reported in terms of blocks, which is Linux's measure of space. This may not be kilobytes, but you can force this using df -k. Some implementations also have a -h switch to report sizes in the most human-readable format.

To find out how much disk space is being used by a directory tree use du,

[phasnip@mijpnb1 ~/Teaching]$ du -h
8.0k	./Linux/Junk
772k	./Linux
980k	.

Notice that the du command gives the space of all subdirectories as well, but that the space for low-level directories is also included in their parent directories.

Because du lists all the subdirectories the output can be overwhelming. Usually we are only interested in the top few directories, so it makes sense to pipe the output through grep

[phasnip@mijpnb1 ~]$ du -h | grep -v '/.*/'
4.1M	./.kde
152k	./.gnome
68k	./Desktop
592k	./.mcop
320k	./.gconf
11M	./.galeon
980k	./Teaching
1.3M	./Rules
58M	.
You can see that the total disk space used is 58 megabytes, and the largest subdirectory is called `.galeon'.


next up previous
Next: Fileservers Up: Introduction to the Linux Previous: Directories That Aren't Directories
Phil Hasnip 2007-08-23