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When you're trying to clean up your filesystems and reclaim some space, one of the first things you'll want to do is to confirm the largest directories and individual files you have. This can be easily done using two Unix commands: find command and du command.
Find files larger than a certain size
It's very simply to find files which are larger than a specified size. The find command accepts a size parameter, and you can specify the limits for file sizes in your command line.
This example finds all the files under /etc directory which are larger than 100k:
root@ubuntu# find /etc -size +100k /etc/ssh/moduli /etc/ssl/certs/ca-certificates.crt /etc/bash_completion
If we look at their sizes, they really are above 100k:
root@ubuntu# ls -l /etc/ssh/moduli /etc/ssl/certs/ca-certificates.crt /etc/bash_completion -rw-r--r-- 1 root root 215938 Apr 10 2007 /etc/bash_completion -rw-r--r-- 1 root root 132777 Feb 19 2007 /etc/ssh/moduli -rw-r--r-- 1 root root 149568 Sep 7 2007 /etc/ssl/certs/ca-certificates.crt
Find files within specified size limits
The real beauty of using find command is that you can specify both the lower and the upper file size limit in one command line. Working off the previous example, we can limit the search to find only files with the size of 100k-150k, quite easily:
root@ubuntu# find /etc -size +100k -size -150k /etc/ssl/certs/ca-certificates.crt /etc/bash_completion
As you can see from the syntax, the size specification can contain a sign – plus or minus indicates whether you're looking for a file with the size above or under a given figure.
Show directory sizes using du
du command takes a little while to run, depending on what directory you pass it as a parameter, but then prints you a list of all the subdirectories along with their sizes. Most common usage is shown below, -s parameter makes the command report a summary of disk usage stats for only the specified directories matching the /usr/* mask (and not their subdirectories), and -k specifies that we want to see the results in kilobytes:
greys@ubuntu$ du -sk /usr/* 4 /usr/X11R6 97664 /usr/bin 24 /usr/games 11628 /usr/include 167812 /usr/lib 0 /usr/lib64 96 /usr/local 25076 /usr/sbin 201500 /usr/share 4 /usr/src
In most Linux systems, this command had been updated to support a -h parameter, which makes sizes even easier to interpret:
greys@ubuntu$ du -sh /usr/* 4.0K /usr/X11R6 96M /usr/bin 24K /usr/games 12M /usr/include 164M /usr/lib 0 /usr/lib64 96K /usr/local 25M /usr/sbin 197M /usr/share 4.0K /usr/src
16 comments ↓
[...] RSS feed to get regular tips & tricks for all flavors of Unix. Thanks for visiting!I see that my Finding Large Files and Directories post is quite popular, yet there are a few more ways to simplify your search for the largest disk [...]
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Thanks a lot, this is the most useful and simple tuition I could find. I went through many UNIX handbooks in the past but it is always cool to refresh.
Glad to have helped you, Klaudio!
Thanks for a great tutorial! I am looking a solution how to display directory sizes in the same way: files can take a little space each other, but if there are 1 million small files in a folder? My question is how to list big folders?
Hi,
Your best bet would be to do something like du -sk /* for starters, and then narrow it down by du -sk /usr/* or something like that.
Thank for your reply! The problem is that I have too many small temporary files in the folder I'm searching and du hangs while executing such a command.
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How do you search for a directory that could be in any other directory?
For example I want to find all "backup" directories but am not sure in which directories they all got saved.
Your tuition helped me on my EEEPC, a modest monster machine that just needed some extra UNIX scripts to perform fine!
A pleasure to be of some help!
Thanks very much. I couldn't remember what the du command was, and spent ages trying to find it again. Cheers
Hi Ben,
Glad to have helped!
Gleb
Please tell me how can i find the largest directory through a bash script who will sum the file in the folder(only the final directories). Thank you
Andrei, du -sk does exactly that, but you need to then sort the output so that it finds the largest.
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