Temporary Modified Environment during External Process Call from Emacs

Question

Is there a convenient and functional (with-...-like) way of temporary modifying environment variables when using shell-comand or start-process?

Thanks in advance, Per

Answer 1

process-environment is a List of overridden environment variables for subprocesses to inherit.

(let ((process-environment (cons "FOO=BAR" process-environment)))
  (shell-command-to-string "echo $FOO"))

->

BAR

Answer 2

server-with-environment looks promising.

server-with-environment is a Lisp macro in `server.el'.

(server-with-environment ENV VARS &rest BODY)

Evaluate BODY with environment variables VARS set to those in ENV. The environment variables are then restored to their previous values.

VARS should be a list of strings. ENV should be in the same format as `process-environment'.