Spooky shell expansions

Let me tell you a story to chill the bones
One that happened to me long time ago

It was a dark and cold night
Plague spreading outside

In the summer of ‘20
I was hacking alone
A little program I wanted to install
Not in /usr/local, but in my $HOME

Young and foolish I was
As I changed the Makefile
PREFIX = ~/.local
And then make I typed

That did not work, of course
And I soon realized
A new folder named ~
Had shown up in my $HOME

“How foolish I was” - I thought
"That must not work,
A Makefile won’t expand
As a shell script sure does”

A folder named ~
When left alone,
Is no reason to fear
Does no harm at all

But care must be taken
And alas, I did not
Soon to learn the hard way
What a ~ gives, a ~ takes away

“Let this be undone!” I exclaimed

As I typed

Four little bytes

$ rm ~