diff --git a/share/Makefile.linting b/share/Makefile.linting
index b13d5892b2ef32dd36c3a51e61faf13886a493ad..5d2d83119ac2f5d783c454d57cfbc74474ed6434 100644
--- a/share/Makefile.linting
+++ b/share/Makefile.linting
@@ -52,17 +52,21 @@ TO_UTF8 ?= iconv -t UTF-8 -f
 
 OCP_INDENT   ?= ocp-indent
 CLANG_FORMAT ?= clang-format
+# wc, tail, head, cmp
 
 # Default values necessary for
 #   LINT_MAKEFILE=<this-makefile> make -f <this-makefile> <lint-target>`
 # Otherwise theses variables are defined into share/Makefile.common
 SED     ?= LC_ALL=C sed
 ISED    ?= sed -i
+FIND    ?= find
 GIT     ?= git
 MKDIR   ?= mkdir -p
 MV      ?= mv
 RM      ?= rm -f
+RMDIR   ?= rm -rf
 TOUCH   ?= touch
+XARGS   ?= xargs --no-run-if-empty
 
 ############
 
@@ -136,7 +140,7 @@ endif
 .PHONY: clean-lint
 clean-lint:
 	echo "Cleaning LINT targets..."
-	rm -rf .lint
+	$(RMDIR) .lint
 
 clean:: clean-lint
 
@@ -157,7 +161,7 @@ LINT.clean-targets+= \
 # Generic rule
 $(LINT.clean-targets):
 	echo "[LINT] Cleaning $(patsubst clean-%,%,$@) targets..."
-	find .lint -type f -name \*.$(patsubst clean-%,%,$@) | xargs -n 10 $(RM)
+	$(FIND) .lint -type f -name \*.$(patsubst clean-%,%,$@) | $(XARGS) -n 10 $(RM)
 
 ###############################
 
@@ -180,7 +184,7 @@ $(LINT.check-targets):
 	$(GIT) ls-files $(LINT.dir) -z \
         | $(GIT) check-attr --stdin -z $@ \
         | $(SED) -zne 'x;n;n;s/^set$$//;t print;b;:print;x;p' \
-        | xargs --null -IXX sh -c '$(LINT.make) LINT_FILE="XX" $@ || exit 255'
+        | $(XARGS) -0 -IXX sh -c '$(LINT.make) LINT_FILE="XX" $@ || exit 255'
 
 #### fix-XXX targets
 
@@ -195,7 +199,7 @@ $(LINT.fix-targets):
 	$(GIT) ls-files $(LINT.dir) -z \
         | $(GIT) check-attr --stdin -z $(patsubst fix-%,check-%,$@) \
         | $(SED) -zne 'x;n;n;s/^set$$//;t print;b;:print;x;p' \
-        | xargs --null -IXX sh -c '$(LINT.make) LINT_FILE="XX" $@ || exit 255'
+        | $(XARGS) -0 -IXX sh -c '$(LINT.make) LINT_FILE="XX" $@ || exit 255'
 
 
 else # LINT_FILE are given
diff --git a/share/Makefile.testing b/share/Makefile.testing
index 352d58e1b5e0c7c7c282b014eb7b7ae3eb336021..7b9b0bca93f251e4018518843568ca8bd9517df4 100644
--- a/share/Makefile.testing
+++ b/share/Makefile.testing
@@ -24,11 +24,24 @@
 # TESTING #
 ###########
 
+################################
+## Default variables
+
 # Defines where to find the ptest_config files
 PURGED_PTEST_DIRS?=tests $(wildcard src/plugins/*/tests)
 PTEST_OPTS?=
 PTEST_DIRS?=$(PURGED_PTEST_DIRS)
 
+############
+# Default values necessary for make -f <this-makefile>
+
+XARGS   ?= xargs --no-run-if-empty
+GREP    ?= grep
+RM      ?= rm -f
+RMDIR   ?= rm -rf
+
+##########################################################################
+
 # Defines the related dune targets
 PTEST_ALIASES=$(addsuffix /ptests,$(addprefix @, tests src/plugins))
 # TODO: uncomments when a dune file is at least generated for all PTEST_DIRS
@@ -58,7 +71,7 @@ else
 
 # PTESTS is internal
 PTESTS=dune exec $(DUNE_BUILD_OPTS) --root ptests -- frama-c-ptests
-#PTESTS=dune exec --root ptests -- frama-c-ptests -v
+#PTESTS=dune exec $(DUNE_BUILD_OPTS) --root ptests -- frama-c-ptests -v
 
 # Note: the public name of ptest.exe is frama-c-ptests
 $(FRAMAC_PTESTS): ptests/ptests.ml
@@ -96,18 +109,18 @@ wtests-help:
 	$(WTESTS) --help
 
 ##########################################################################
-## Removes all dune files generated for testing: xargs -n 10 avoids a too long line
+## Removes all dune files generated for testing
 
 .PHONY: purge-tests
 purge-tests:
 	find $(PURGED_PTEST_DIRS) -name dune \
-        | grep -e "/oracle.*/dune\|/result.*/dune" \
-        | xargs --no-run-if-empty -n 10 rm
+        | $(GREP) -e "/oracle.*/dune\|/result.*/dune" \
+        | $(XARGS) -n 10 $(RM)
 
 # Force the full cleaning of the testing environment
 .PHONY: clean-tests
 clean-tests: purge-tests
-	rm -rf $(addprefix _build/default/,$(PURGED_PTEST_DIRS))
+	$(RMDIR) $(addprefix _build/default/,$(PURGED_PTEST_DIRS))
 
 ##########################################################################
 ## Generates all dune files used for testing