[2-11] How do I save an executable image of my loaded Lisp system? How do I run a Unix command in my Lisp? How do I exit Lisp? Access environment variables?

There is no standard for dumping a Lisp image. Here are the
commands from some lisp implementations:
 Lucid: DISKSAVE
 Symbolics: Save World [CP command]
 CMU CL: SAVE-LISP
 Franz Allegro: EXCL:DUMPLISP (documented) 
 SAVE-IMAGE (undocumented)
 Medley: IL:SYSOUT or IL:MAKESYS
 MCL: SAVE-APPLICATION <pathname>
 &key :toplevel-function :creator :excise-compiler
 :size :resources :init-file :clear-clos-caches
 KCL: (si:save-system "saved_kcl")
 LispWorks:		LW:SAVE-IMAGE
Be sure to garbage collect before dumping the image. You may need to
experiment with the kind of garbage collection for large images, and
may find better results if you build the image in stages.
There is no standard for running a Unix shell command from Lisp,
especially since not all Lisps run on top of Unix. Here are the
commands from some Lisp implementations:
 Allegro: EXCL:RUN-SHELL-COMMAND (command &key input output
 error-output wait if-input-does-not-exist
 if-output-exists if-error-output-exists)
 Lucid: RUN-PROGRAM (name 
 &key input output
 error-output (wait t) arguments
 (if-input-does-not-exist :error)
 (if-output-exists :error)
 (if-error-output-exists :error))
 KCL: SYSTEM 
 For example, (system "ls -l").
 You can also try RUN-PROCESS and EXCLP, but they
 don't work with all versions of KCL.
 CMU CL: RUN-PROGRAM (program args
			 &key (env *environment-list*) (wait t) pty input
			 if-input-does-not-exist output
			 (if-output-exists :error) (error :output) 
			 (if-error-exists :error) status-hook before-execve)
 LispWorks: FOREIGN:CALL-SYSTEM-SHOWING-OUTPUT
To toggle source file recording and cross-reference annotations, use
 Allegro: excl:*record-source-file-info*
			excl:*load-source-file-info* 
			excl:*record-xref-info*
			excl:*load-xref-info*
 LispWorks: (toggle-source-debugging nil)
Memory management:
 CMU CL: (bytes-consed-between-gcs) [this is setfable]
 Lucid:		(change-memory-management 
 			 &key growth-limit expand expand-reserved)
 Allegro:		*tenured-bytes-limit*
 LispWorks: LW:GET-GC-PARAMETERS
 (use LW:SET-GC-PARAMETERS to change them)
Environment Variable Access:
 Allegro: (sys:getenv var)
 (sys:setenv var value) or (setf (sys:getenv var) value)
 Lucid: (environment-variable var)
 (set-environment-variable var value)
 CMU CL 17: (cdr (assoc (intern var :keyword) *environment-list*))
 {A}KCL, GCL: (system:getenv var)
 CLISP: (system::getenv var)
Exiting/Quitting:
 CLISP: EXIT
 Allegro: EXIT (&optional excl::code &rest excl::args
 &key excl::no-unwind excl::quiet)
 LispWorks: BYE (&optional (arg 0))
 Lucid: QUIT (&optional (lucid::status 0))
 CMU CL: QUIT (&optional recklessly-p)