diff --git a/Makefile b/Makefile
index 32f1abe..91cac62 100644
--- a/Makefile
+++ b/Makefile
@@ -42,7 +42,7 @@ $(DC_MAKEFILE_DIR)/bin/bootstrap/builder: $(DC_MAKEFILE_DIR)/bootstrap
 # Then build the cli tools, using the bootstrapper
 $(DC_PREFIX)/bin/dc-tooling-%: $(DC_MAKEFILE_DIR)/source/core/*.sh $(DC_MAKEFILE_DIR)/source/cli-tooling/%
 	$(call title, $@)
-	$(DC_MAKEFILE_DIR)/bin/bootstrap/builder --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT license" --author="dubo-dubon-duponey" --description="another fancy (tooling) piece of shcript" --with-git-info $^
+	$(DC_MAKEFILE_DIR)/bin/bootstrap/builder --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT License" --author="dubo-dubon-duponey" --description="another fancy (tooling) piece of shcript" --with-git-info $^
 
 #######################################################
 # Base building tasks
@@ -51,22 +51,22 @@ $(DC_PREFIX)/bin/dc-tooling-%: $(DC_MAKEFILE_DIR)/source/core/*.sh $(DC_MAKEFILE
 # Builds the main library
 $(DC_PREFIX)/lib/dc-sh-art: $(DC_MAKEFILE_DIR)/source/core/*.sh
 	$(call title, $@)
-	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT license" --author="dubo-dubon-duponey" --description="the library version" --with-git-info $^
+	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT License" --author="dubo-dubon-duponey" --description="the library version" --with-git-info $^
 
 # Builds the extensions
 $(DC_PREFIX)/lib/dc-sh-art-extensions: $(DC_MAKEFILE_DIR)/source/extensions/**/*.sh
 	$(call title, $@)
-	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT license" --author="dubo-dubon-duponey" --description="extensions" $^
+	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT License" --author="dubo-dubon-duponey" --description="extensions" $^
 
 # Builds all the CLIs that depend just on the main library
 $(DC_PREFIX)/bin/dc-%: $(DC_PREFIX)/lib/dc-sh-art $(DC_MAKEFILE_DIR)/source/cli/%
 	$(call title, $@)
-	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT license" --author="dubo-dubon-duponey" --description="another fancy piece of shcript" $^
+	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT License" --author="dubo-dubon-duponey" --description="another fancy piece of shcript" $^
 
 # Builds all the CLIs that depend on the main library and extensions
 $(DC_PREFIX)/bin/dc-%: $(DC_PREFIX)/lib/dc-sh-art $(DC_PREFIX)/lib/dc-sh-art-extensions $(DC_MAKEFILE_DIR)/source/cli-ext/%
 	$(call title, $@)
-	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT license" --author="dubo-dubon-duponey" --description="another fancy piece of shcript" $^
+	$(DC_PREFIX)/bin/dc-tooling-build --destination="$(shell dirname $@)" --name="$(shell basename $@)" --license="MIT License" --author="dubo-dubon-duponey" --description="another fancy piece of shcript" $^
 
 #######################################################
 # Tasks to be called on
@@ -89,7 +89,7 @@ lint-signed: $(DC_MAKEFILE_DIR)/bin/bootstrap/builder $(DC_PREFIX)/bin/dc-toolin
 
 # Linter
 #	XXX broken for now $(DC_PREFIX)/bin/dc-tooling-lint $(DC_PREFIX)/bin
-lint-code: $(DC_MAKEFILE_DIR)/bin/bootstrap/builder $(DC_PREFIX)/bin/dc-tooling-lint build-library
+lint-code: $(DC_MAKEFILE_DIR)/bin/bootstrap/builder $(DC_PREFIX)/bin/dc-tooling-lint build-library build-binaries
 	$(call title, $@)
 	$(DC_PREFIX)/bin/dc-tooling-lint $(DC_MAKEFILE_DIR)/bootstrap
 	$(DC_PREFIX)/bin/dc-tooling-lint $(DC_MAKEFILE_DIR)/source
diff --git a/source/cli-tooling/build/base-build.sh b/source/cli-tooling/build/base-build.sh
index df613b3..d67b383 100644
--- a/source/cli-tooling/build/base-build.sh
+++ b/source/cli-tooling/build/base-build.sh
@@ -21,7 +21,7 @@ dc-tools::build::append(){
 dc-tools::build::header(){
   local destination="$1"
   local shortdesc="${2:-another fancy piece of shcript}"
-  local license="${3:-MIT license}"
+  local license="${3:-MIT License}"
   local owner="${4-dubo-dubon-duponey}"
   local name
   name="$(basename "$1")"
diff --git a/source/cli/http/cmd.sh b/source/cli/http/cmd.sh
index 53b6f3a..8e0b077 100644
--- a/source/cli/http/cmd.sh
+++ b/source/cli/http/cmd.sh
@@ -1,16 +1,13 @@
 #!/usr/bin/env bash
 
-readonly CLI_VERSION="0.0.1"
-readonly CLI_LICENSE="MIT License"
 readonly CLI_DESC="like curl, in a nicer json-way"
-readonly CLI_USAGE="[-s] [--insecure] url [method] [payload] [...headers]"
 
 # Initialize
 dc::commander::initialize
-dc::commander::declare::arg 1 ".+" "" "url" "url..."
-dc::commander::declare::arg 2 ".+" "optional" "method" "http method"
+dc::commander::declare::arg 1 ".+" "" "url" "url to query"
+dc::commander::declare::arg 2 ".+" "optional" "method" "http method (default to GET)"
 dc::commander::declare::arg 3 ".+" "optional" "payload" "payload to post"
-dc::commander::declare::arg 4 ".+" "optional" "[...headers]" "optional additional headers to be passed"
+dc::commander::declare::arg 4 ".+" "optional" "[...headers]" "additional headers to be passed"
 # Start commander
 dc::commander::boot
 
diff --git a/source/core/abash.sh b/source/core/abash.sh
index bcaf9a1..0d480d8 100644
--- a/source/core/abash.sh
+++ b/source/core/abash.sh
@@ -17,3 +17,11 @@ _have_bash(){
 }
 
 _have_bash
+
+_gnu_grep(){
+  if grep --version | grep -q gnu; then
+    readonly _GNUGREP="true"
+  fi
+}
+
+_gnu_grep
diff --git a/source/core/commander.sh b/source/core/commander.sh
index edaded8..e1b2e88 100644
--- a/source/core/commander.sh
+++ b/source/core/commander.sh
@@ -10,7 +10,7 @@
 
 readonly DC_CLI_NAME=$(basename "$0")
 readonly DC_CLI_VERSION="$DC_VERSION (core script)"
-readonly DC_CLI_LICENSE="MIT license"
+readonly DC_CLI_LICENSE="MIT License"
 readonly DC_CLI_DESC="A fancy piece of shcript"
 export DC_CLI_USAGE=""
 export DC_CLI_OPTS=()
@@ -72,7 +72,11 @@ dc::commander::declare::arg(){
   local optional="$3"
   local fancy="$4"
   local description="$5"
-  local gf="${6:--Ei}"
+  if [ "$_GNUGREP" ]; then
+    gf="${6:--Pi}"
+  else
+    gf="${6:--Ei}"
+  fi
 
   local var="DC_PARGV_$number"
   local varexist="DC_PARGE_$number"
@@ -122,7 +126,12 @@ dc::commander::declare::flag(){
   local optional="$3"
   local description="$4"
   local alias="$5"
-  local gf="${6:--Ei}"
+  local gf
+  if [ "$_GNUGREP" ]; then
+    gf="${6:--Pi}"
+  else
+    gf="${6:--Ei}"
+  fi
 
   local display="--$name"
   local long="--$name"
diff --git a/tests/unit/arg.sh b/tests/unit/arg.sh
new file mode 100644
index 0000000..c65fae3
--- /dev/null
+++ b/tests/unit/arg.sh
@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+testArgGrep() {
+  # shellcheck disable=SC2034
+  DC_PARGV_1=foobar
+  # shellcheck disable=SC2034
+  DC_PARGE_1=true
+  local result
+  # shellcheck disable=SC2034
+  result="$(dc::commander::declare::arg 1 "^foo(?:bar)?$" "" "a flag" "a flag")"
+  local exit=$?
+  dc-tools::assert::equal "$exit" "0"
+
+  # shellcheck disable=SC2034
+  result="$(dc::commander::declare::arg 1 "^foo(?:abar)?$" "" "another flag" "another flag")"
+  local exit=$?
+  dc-tools::assert::equal "$exit" "$ERROR_ARGUMENT_INVALID"
+}