How to delete blank lines in Vim

Vim is a powerful tool. I often paste raw data into Vim in order to format it in a specific way, and sometimes I need to clean up the file by removing many blank lines. Fortunately there is a simple Vim command to remove all blank lines in a file.

tl;dr

:g/^$/d

See below for more details.

1

While in normal mode, type:

:g/^$/d

Here's a breakdown of this command.

Description
:gThis will execute a command globally on all lines that match a regex (to follow).
/^$/This is the regex. The forward slashes enclose the pattern, which is: ^$. This is a regex pattern that matches the beginning of a line (^) and the end of a line ($) with nothing in between, which is the definition of a blank line :)
dThis is the command to be executed. d stands for delete!

So when you put it all together, you find all blank lines globally across the whole file, and delete them.