There are several shells for Emacs, but none can match the versatility and integration with Emacs like Eshell. Eshell is a shell written entirely in Emacs-Lisp, and it replicates most of the features and commands from GNU CoreUtils and the Bourne-like shells. So by re-writing common commands like
cpin Emacs-Lisp, Eshell will function identically on any environment Emacs itself runs on.
Unfortunately, there is a problem: Eshell is woefully underdocumented — a rare sight in GNU Emacs — so I’ve compiled this guide to help people make full use of what Eshell has to offer.