For example, how to get the size of sub-directory with max-depth 1?
How to sort the output by each directory's size from the output of the du -h?
$ du -d 1 -h
$ du -d 1 -h | sort -hr
sort -h gives the trick, and -r further sort it in the reverse order.
For more options that are available for du utility, you can use du --help to see more.
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