vim

Numeric sort

:sort n

remove duplicate lines

:%sort u

Sorting IP addresses

:%sort n /\.\d\+\./

To adjust the indent on lines

V    select lines
>    indent

# block

Ctrl v
shift I
#
ESC ESC

replace sequences of spaces with a single tab

:'<,'>s/ \+/\t/g

Links

1. https://wiki.debian.org/vim
2. vim tutor
3. https://vimdoc.sourceforge.net/htmldoc/syntax.html
4. https://www.cheatsheet.wtf/vim/ 
5. https://devhints.io/vim