How to convert all text to lowercase in Vim

Question

How do you convert all text in Vim to lowercase? Is it even possible?

Answer 1

Similar to mangledorf's solution, but shorter and layman friendly

:%s/.*/\L&/g

Answer 2

If you are running under a flavor of Unix

:0,$!tr "[A-Z]" "[a-z]"

Answer 3

Many ways to skin a cat... here's the way I just posted about:

:%s/[A-Z]/\L&/g

Likewise for upper case:

:%s/[a-z]/\U&/g

I prefer this way because I am using this construct (:%s/[pattern]/replace/g) all the time so it's more natural.

Answer 4

I had a similar issue, and I wanted to use ":%s/old/new/g", but ended up using two commands:

:0
gu:$