Re: Relation between the value of shell-file-name and explicit-shell-file-name

[Stuart D. Herring]

> What is the relation between the values of these two variables? Could
> the doc strings please mention something about it? (Does
> explicit-shell-file-name override shell-file-name for explicitly
> requested shells? Are those the shells started with M-x shell? )

`explicit-shell-file-name' is only ever used by M-x shell.  It does

(or explicit-shell-file-name
    (getenv "ESHELL") shell-file-name)

which obviously prefers $ESHELL to `shell-file-name' and
`explicit-shell-file-name' to $ESHELL.  Note that it was different in
Emacs 21:

(or explicit-shell-file-name
    (getenv "ESHELL")
    (getenv "SHELL")
    "/bin/sh")

Here `shell-file-name' is absent.  The idea is that e-s-f-n is the
"personal" shell and s-f-n is the "utility" shell used by such things as
M-! and (unless you customize `ediff-shell') M-x ediff.

What do you want added to e-s-f-n's doc string to clarify this?

Davis

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