Intro To 'du' Command In Linux

2023-05-18 - By Robert Elder

     I use the 'du' command to show the amount of disk space taken up by parts of my file system.  By default, the 'du' command will print the amount of disk space used in kilobytes:

du

10244	./manifestos
2052	./pictures/old
4104	./pictures
1048584	./backups
1062936	.

     I can make the output more clear by including the '-h' flag:

du -h

11M	./manifestos
2.1M	./pictures/old
4.1M	./pictures
1.1G	./backups
1.1G	.

     You can list specific files or directories to see counts for only these items:

du -h pictures backups

2.1M	pictures/old
4.1M	pictures
1.1G	backups

     You can see a total count printed at the end using the '-c' flag:

du -h -c pictures backups

2.1M	pictures/old
4.1M	pictures
1.1G	backups
1.1G	total

     The '-s' flag can be used to omit the printing of subdirectories in the output:

du -h -c -s pictures backups

4.1M	pictures
1.1G	backups
1.1G	total

Finding the Largest File(s) In The Filesystem Using The 'du' Command

     I can use the 'du' command in a shell pipe to find the 5 largest files within the current directory:

find . -type f -exec du {} \; | sort -n | tail -n 5

1024	./pictures/old/cat.jpg
1024	./pictures/old/dog.jpg
2048	./manifestos/software-bloat-is-reducing-GDP.txt
8192	./manifestos/why-tabs-are-better-than-spaces.txt
1048580	./backups/my-huge-backup.dat

Finding the Largest File(s) Or Directories In The Filesystem Using The 'du' Command

     I can also list the 5 largest files or directories within the current directory using this command:

du -a | sort -n | tail -n 5

8192	./manifestos/why-tabs-are-better-than-spaces.txt
10244	./manifestos
1048580	./backups/my-huge-backup.dat
1048584	./backups
1062936	.

     You could also run this on a different directory like this:

du -a /my-favourite-directory | sort -n | tail -n 5

     And that's why the 'du' command is my favourite Linux command.