Linux

How to check disk space on Unix servers

I recently switched from a Windows server 2016 to a FreeBSD Unix server. I need to check disk space on Unix command line. How do I find out disk space utilization information using the Unix command-line option?

Unix family of operating systems offer the following commands to check disk space usage as per your needs.

 

Check disk space on Unix operating system

Unix command to check disk space:

  1. df command – Shows the amount of disk space used and available on Unix file systems.
  2. du command – Display disk usage statistic for each directory on Unix server.

How to display Unix disk usage statistics

See disk usage for all files in the current directory. Run:
du -a
To get the disk usage of a directory tree and each of its subtrees for /home/vivek, enter:
du /home/vivek
However, it is possible to see outout 1024-byte blocks if you pass the -k switch, enter:
du -k /home/vivek
Want to see total disk usage of a directory tree? Try:
du -s /home/vivek

248088	/home/vivek

One can summarize disk usage for a specific directory as follows:
du -hs /home

1.4G	/home

Next let us show name and size of all py (Python) files in a specific directory. Also display grand total at the end:
du -ch /home/vivek/project/mgt1.2/*.py

Getting help about du command

Try running the following man command or see online man page here:
man du
whatis du

How to display free disk space info on Unix

To view the amount of free space in the file system, try df command:
df
Check disk space on Unix using df command
Want to show information about /jails/www/ file system in 1024-byte blocks format, run:
df -k /jails/www/

Filesystem      1024-blocks    Used       Avail Capacity  Mounted on
zroot/jails/www 10745194355 3152328 10742042027     0%    /jails/www

Similarly, to show information about /jails/www file system in MB blocks format, enter:
df -m /jails/www/

Filesystem      1M-blocks Used    Avail Capacity  Mounted on
zroot/jails/www  10493353 3078 10490275     0%    /jails/www

How about GB blocks format for /jails/www file system?, Try:
df -g /jails/www/

Filesystem      1G-blocks Used Avail Capacity  Mounted on
zroot/jails/www     10247    3 10244     0%    /jails/www

Display a grand total

Pass the -c option:
df -c
Some version of Unix operating systems can display output in human readable format. In other words, Use unit suffixes: Byte, Kibibyte, Mebibyte, Gibibyte, Tebibyte and Pebibyte:
df -H
Sample outputs:

Filesystem                                 Size    Used   Avail Capacity  Mounted on
zroot/ROOT/default                          11T    4.2G     11T     0%    /
devfs                                      1.0k    1.0k      0B   100%    /dev
fdescfs                                    1.0k    1.0k      0B   100%    /dev/fd
zroot/iocage                                11T    148k     11T     0%    /iocage
zroot/iocage/download                       11T    131k     11T     0%    /iocage/download
zroot/iocage/download/11.2-RELEASE          11T    285M     11T     0%    /iocage/download/11.2-RELEASE
zroot/iocage/images                         11T    131k     11T     0%    /iocage/images
zroot/iocage/jails                          11T    131k     11T     0%    /iocage/jails
zroot/iocage/log                            11T    131k     11T     0%    /iocage/log
zroot/iocage/releases                       11T    131k     11T     0%    /iocage/releases
zroot/iocage/releases/11.2-RELEASE          11T    131k     11T     0%    /iocage/releases/11.2-RELEASE
zroot/iocage/releases/11.2-RELEASE/root     11T    1.2G     11T     0%    /iocage/releases/11.2-RELEASE/root
zroot/iocage/templates                      11T    131k     11T     0%    /iocage/templates
zroot/jails                                 11T    131k     11T     0%    /jails
zroot/jails/fullbasejail                    11T    364M     11T     0%    /jails/fullbasejail
zroot/jails/rsnapshot                       11T    209G     11T     2%    /jails/rsnapshot
zroot/jails/www                             11T    3.2G     11T     0%    /jails/www
zroot/tmp                                   11T    131k     11T     0%    /tmp
zroot/usr/home                              11T    220k     11T     0%    /usr/home
zroot/usr/ports                             11T    1.0G     11T     0%    /usr/ports
zroot/usr/src                               11T    1.7G     11T     0%    /usr/src
zroot/var/audit                             11T    131k     11T     0%    /var/audit
zroot/var/crash                             11T    131k     11T     0%    /var/crash
zroot/var/log                               11T    4.2M     11T     0%    /var/log
zroot/var/mail                              11T    131k     11T     0%    /var/mail
zroot/var/tmp                               11T    131k     11T     0%    /var/tmp
zroot                                       11T    131k     11T     0%    /zroot
devfs                                      1.0k    1.0k      0B   100%    /jails/rsnapshot/dev
devfs                                      1.0k    1.0k      0B   100%    /jails/www/dev

See df command man page here or by typing the following command for more info:
man df

Conclusion

You learned how to see free and used disk space as well as disk usage statistics on Unix systems.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

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