In Linux, managing disk space effectively involves understanding the size of both files and directories. Tools like ls and stat give basic details, but du is designed specifically for checking directory size and folder size. It shows not just the size of individual files, but also recursively provides the size of all contents in a directory.
The du command can display the size of files and directories in various formats, making it a versatile tool for keeping track of disk usage. This command can be used to find large folders or files that might need to be cleaned up to free up space. It also supports various options that allow users to customize the output, such as showing sizes in human-readable formats or specifying how deep to go when inspecting nested directories.
For administrators or users managing Linux systems, knowing how to check directory sizes is a crucial part of system maintenance. With du, you can identify which directories or files are taking up the most space. This makes it easier to clean up unnecessary files and better manage available storage, especially in environments with limited disk space.
Related: How to check disk space and usage in Linux
Related: How to free disk space on Linux
Steps to check directory and file sizes in Linux:
- Check the size of a specific file.
$ du Documents/random.txt 16 Documents/random.txt
Shows the file size in 1K blocks by default.
- Display the size in a human-readable format.
$ du -h Documents/random.txt 16K Documents/random.txt
Displays the size in kilobytes (K), megabytes (M), or gigabytes (G), depending on the file size.
- Show the size of all folders within a directory recursively.
$ du -h Documents/ 21M Documents/Finance 4.0K Documents/Secret/Empty 40K Documents/Secret 21M Documents/
This command will display the size of each folder and subfolder within the directory.
- Limit the depth of recursive folder size display.
$ du -h --max-depth=1 Documents/ 21M Documents/Finance 40K Documents/Secret 21M Documents/
Setting max-depth allows you to control how deep to explore subdirectories.
- Show folder sizes, including the total size.
$ du -hc Documents/ 21M Documents/Finance 4.0K Documents/Secret/Empty 40K Documents/Secret 21M Documents/ 21M total
- Display the total size of a folder.
$ du -hs Documents/ 21M Documents/
The -s flag summarizes the size of the directory without listing individual files or subfolders.
- Check system folder sizes with elevated permissions.
$ sudo du -hs /var/cache/ [sudo] password for user: 117M /var/cache/
Useful for checking sizes in system directories that require root access.
- Show non-recursive folder sizes using a wildcard.
$ sudo du -hs /var/cache/* 6.2M /var/cache/apparmor 16M /var/cache/app-info 75M /var/cache/apt 6.1M /var/cache/cracklib 32K /var/cache/cups 5.2M /var/cache/debconf 40K /var/cache/dictionaries-common 2.7M /var/cache/fontconfig 2.1M /var/cache/fwupd 0 /var/cache/fwupdmgr 60K /var/cache/ldconfig 2.1M /var/cache/man 8.0K /var/cache/PackageKit 8.0K /var/cache/private 4.0K /var/cache/realmd 2.2M /var/cache/snapd
This will display the size of each folder inside var/cache without diving into subdirectories.
- Use the du command with more options.
$ du --help Usage: du [OPTION]... [FILE]... or: du [OPTION]... --files0-from=F Summarize disk usage of the set of FILEs, recursively for directories. Mandatory arguments to long options are mandatory for short options too. -0, --null end each output line with NUL, not newline -a, --all write counts for all files, not just directories --apparent-size print apparent sizes, rather than disk usage; although the apparent size is usually smaller, it may be larger due to holes in ('sparse') files, internal fragmentation, indirect blocks, and the like -B, --block-size=SIZE scale sizes by SIZE before printing them; e.g., '-BM' prints sizes in units of 1,048,576 bytes; see SIZE format below -b, --bytes equivalent to '--apparent-size --block-size=1' -c, --total produce a grand total -D, --dereference-args dereference only symlinks that are listed on the command line -d, --max-depth=N print the total for a directory (or file, with --all) only if it is N or fewer levels below the command line argument; --max-depth=0 is the same as --summarize --files0-from=F summarize disk usage of the NUL-terminated file names specified in file F; if F is -, then read names from standard input -H equivalent to --dereference-args (-D) -h, --human-readable print sizes in human readable format (e.g., 1K 234M 2G) --inodes list inode usage information instead of block usage -k like --block-size=1K -L, --dereference dereference all symbolic links -l, --count-links count sizes many times if hard linked -m like --block-size=1M -P, --no-dereference don't follow any symbolic links (this is the default) -S, --separate-dirs for directories do not include size of subdirectories --si like -h, but use powers of 1000 not 1024 -s, --summarize display only a total for each argument -t, --threshold=SIZE exclude entries smaller than SIZE if positive, or entries greater than SIZE if negative --time show time of the last modification of any file in the directory, or any of its subdirectories --time=WORD show time as WORD instead of modification time: atime, access, use, ctime or status --time-style=STYLE show times using STYLE, which can be: full-iso, long-iso, iso, or +FORMAT; FORMAT is interpreted like in 'date' -X, --exclude-from=FILE exclude files that match any pattern in FILE --exclude=PATTERN exclude files that match PATTERN -x, --one-file-system skip directories on different file systems --help display this help and exit --version output version information and exit Display values are in units of the first available SIZE from --block-size, and the DU_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE environment variables. Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set). The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000). Binary prefixes can be used, too: KiB=K, MiB=M, and so on. GNU coreutils online help: <https://www.gnu.org/software/coreutils/> Full documentation <https://www.gnu.org/software/coreutils/du> or available locally via: info '(coreutils) du invocation'Related: du man page
Mohd Shakir Zakaria is a cloud architect with deep roots in software development and open-source advocacy. Certified in AWS, Red Hat, VMware, ITIL, and Linux, he specializes in designing and managing robust cloud and on-premises infrastructures.
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