How to analyse disk usage in command line linux?

You might also want to try the NCurses Disk Usage aka ncdu.

Use it like ncdu -x -q if you're invoking it remotely (e. g. via ssh) and ncdu -x otherwise.

ncdu 1.6 ~ Use the arrow keys to navigate, press ? for help
    --- /home/geek -----------------------------------------------------------------
       27.6MiB  /qm test 1 rework
      312.0kiB  /sidebar
       88.0kiB  /rackerhacker-MySQLTuner-perl-6add618
        8.0kiB  /.w3m
        4.0kiB  /.cache
    e   4.0kiB  /.ssh
      160.0kiB   ng.tar.gz
       76.0kiB   plowshare_1~svn1673-1_all.deb
        4.0kiB   .bashrc
        4.0kiB   .bash_history
        4.0kiB   .profile
        4.0kiB   .htoprc
        4.0kiB   .bash_logout
        0.0  B   .lesshst

This is available under Mac OS X too.

The following flags to the command line might be helpful:

-q Quiet mode, doesn't update the screen 10 times a second
   while scanning, reduces network bandwidth used

-x Don't cross filesystem borders (don't descend into a
   directory which is a mounted disk)

Thanks to Sorin Sbarnea.

Use some combination of the commands and options:

du --max-depth=1 2> /dev/null | sort -n -r | head -n20

to view only the largest few. If you'd like to use it a lot, then bind it to an alias, e.g. in bash by adding to ~/.bashrc

alias largest='du --max-depth=1 2> /dev/null | sort -n -r | head -n20'

I would like to recommend dutree, which offers a hierachical visualization.

You can select more or less levels of detail, and exclude paths for better control of visualization. You can also compare different paths.

It is implemented in Rust, fast and efficient.

$ dutree -h
Usage: dutree [options] <path> [<path>..]

Options:
    -d, --depth [DEPTH] show directories up to depth N (def 1)
    -a, --aggr [N[KMG]] aggregate smaller than N B/KiB/MiB/GiB (def 1M)
    -s, --summary       equivalent to -da, or -d1 -a1M
    -u, --usage         report real disk usage instead of file size
    -b, --bytes         print sizes in bytes
    -f, --files-only    skip directories for a fast local overview
    -x, --exclude NAME  exclude matching files or directories
    -H, --no-hidden     exclude hidden files
    -A, --ascii         ASCII characters only, no colors
    -h, --help          show help
    -v, --version       print version number