3.4 History

Eshell knows a few built-in variables:

$+

This variable always contains the current working directory.

$-

This variable always contains the previous working directory (the current working directory from before the last cd command).

$_

It refers to the last argument of the last command.

$$

This is the result of the last command. In case of an external command, it is t or nil.

$?

This variable contains the exit code of the last command (0 or 1 for Lisp functions, based on successful completion).