Tilde Expansion

~

Expands to the Home-Directory (i.e. to $HOME)

~username

Expands to the Home of the user username

~+

Expands to the Present Working Directory (i.e. to $PWD or pwd)

~-

Expands to the old PWD (i.e. $OLDPWD)

~N

~+N

~-N

Expands to a path in the directory stack (view dirs, pushd, popd for details)

Example

echo My ~ is my castle