diff --git a/makefiles/lint/shell.mk b/makefiles/lint/shell.mk
index 9923b72..3c04539 100644
--- a/makefiles/lint/shell.mk
+++ b/makefiles/lint/shell.mk
@@ -1,8 +1,8 @@
 # -*- makefile -*-
 # -----------------------------------------------------------------------
-# Copyright 2017-2023 Open Networking Foundation
+# Copyright 2017-2023 Open Networking Foundation (ONF) and the ONF Contributors
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
+# Licensed under the Apache License, Version 2.0 (the "License")
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
@@ -15,19 +15,73 @@
 # limitations under the License.
 # -----------------------------------------------------------------------
 
-JSON_FILES ?= $(error JSON_FILES= is required)
+$(if $(DEBUG),$(warning ENTER))
 
-.PHONY: lint-shell
+##-------------------##
+##---]  GLOBALS  [---##
+##-------------------##
+.PHONY: lint-shell lint-shell-all lint-shell-modified
 
-lint : lint-shell
+have-shell-sources := $(if $(strip $(SHELL_SOURCES)),true)
+SHELL_SOURCES      ?= $(error SHELL_SOURCES= required)
 
-lint-shell:
+## -----------------------------------------------------------------------
+## Intent: Use the shell command to perform syntax checking.
+##   % make lint
+##   % make lint-shell-all
+## -----------------------------------------------------------------------
+ifndef NO-LINT-SHELL
+  lint-shell-mode := $(if $(have-shell-sources),modified,all)
+  lint : lint-shell-$(lint-shell-mode)
+endif# NO-LINT-SHELL
+
+## -----------------------------------------------------------------------
+## Intent: exhaustive shell syntax checking
+## -----------------------------------------------------------------------
+shellcheck-find-args := $(null)
+shellcheck-find-args += -name '$(venv-name)'
+shellcheck-find-args += -o -name 'staging'
+lint-shell-all:
+	$(MAKE) --no-print-directory lint-shellcheck-install
+
+	find . \( $(shellcheck-find-args) \) -prune -name '*.sh' -print0 \
+	    | $(xargs-n1-clean) shellcheck
+
+## -----------------------------------------------------------------------
+## Intent: check deps for format and python3 cleanliness
+## Note:
+##   shell --py3k option no longer supported
+## -----------------------------------------------------------------------
+lint-shell-modified:
+	$(MAKE) --no-print-directory lint-shell-install
+
+	shellcheck $(SHELL_SOURCES)
+
+## -----------------------------------------------------------------------
+## Intent:
+## -----------------------------------------------------------------------
+.PHONY: lint-shellcheck-install
+lint-shellcheck-install:
+	@echo
+	@echo "** -----------------------------------------------------------------------"
+	@echo '** command shell syntax checking'
+	@echo "** -----------------------------------------------------------------------"
+
+        # {apt-get,rpm,yum} install shellcheck
 	shellcheck --version
-	find . \( -name 'staging' -o -name 'vst_venv' \) -prune \
-	    -o -name '*.sh' ! -name 'activate.sh' -print0 \
-	| xargs -0 -n1 shellcheck
+	@echo
 
+## -----------------------------------------------------------------------
+## Intent: Display command usage
+## -----------------------------------------------------------------------
 help::
-	@echo "  lint-shell           Syntax check bash,bourne,etc sources"
+	@echo '  lint-shell          Syntax check sources using shellcheck'
+  ifdef VERBOSE
+	@echo '  $(MAKE) lint-shell SHELL_SOURCES=...'
+	@echo '  lint-shell-modified  shell checking: only modified'
+	@echo '  lint-shell-all       shell checking: exhaustive'
+  endif
+
+$(if $(DEBUG),$(warning LEAVE))
 
 # [EOF]