diff --git a/Makefile b/Makefile
index a5c4aa41d..9a43fef14 100644
--- a/Makefile
+++ b/Makefile
@@ -402,6 +402,7 @@ lint:
 	flake8 --config=scripts/flake8.cfg lib/py/images/pb2dict.py
 	shellcheck scripts/*.sh
 	shellcheck scripts/ci/*.sh scripts/ci/apt-install
+	shellcheck test/others/crit/*.sh
 
 codecov: SHELL := $(shell which bash)
 codecov:
diff --git a/test/others/crit/test.sh b/test/others/crit/test.sh
index a85b4c3b2..9d30575c4 100755
--- a/test/others/crit/test.sh
+++ b/test/others/crit/test.sh
@@ -1,8 +1,14 @@
+#!/bin/bash
+# shellcheck disable=SC1091,SC2002
+
+set -x
+
 source ../env.sh
 
 images_list=""
 
 function _exit {
+	# shellcheck disable=SC2181
 	if [ $? -ne 0 ]; then
 		echo "FAIL"
 		exit 1
@@ -13,37 +19,89 @@ function gen_imgs {
 	setsid ./loop.sh < /dev/null &> /dev/null &
 	PID=$!
 	$CRIU dump -v4 -o dump.log -D ./ -t $PID
+	# shellcheck disable=SC2181
 	if [ $? -ne 0 ]; then
 		kill -9 $PID
 		_exit 1
 	fi
 
-	images_list=$(ls -1 *.img)
+	images_list=$(ls -1 ./*.img)
 	if [ -z "$images_list" ]; then
 		echo "Failed to generate images"
 		_exit 1
 	fi
 }
 
-function run_test {
+function run_test1 {
 	for x in $images_list
 	do
 		echo "=== $x"
-		if [[ $x == pages* ]]; then
+		if [[ $x == *pages* ]]; then
 			echo "skip"
 			continue
 		fi
 
 		echo "  -- to json"
-		$CRIT decode -o "$x"".json" --pretty < $x || _exit $?
+		$CRIT decode -o "$x"".json" --pretty < "$x" || _exit $?
 		echo "  -- to img"
 		$CRIT encode -i "$x"".json" > "$x"".json.img" || _exit $?
 		echo "  -- cmp"
-		cmp $x "$x"".json.img" || _exit $?
+		cmp "$x" "$x"".json.img" || _exit $?
 
 		echo "=== done"
 	done
 }
 
+
+function run_test2 {
+	mapfile -t array <<< "$images_list"
+
+	PROTO_IN=${array[0]}
+	JSON_IN=$(mktemp -p ./ tmp.XXXXXXXXXX.json)
+	OUT=$(mktemp -p ./ tmp.XXXXXXXXXX.log)
+
+	# prepare
+	${CRIT} decode -i "${PROTO_IN}" -o "${JSON_IN}"
+
+	# proto in - json out decode
+	cat "${PROTO_IN}" | ${CRIT} decode || _exit 1
+	cat "${PROTO_IN}" | ${CRIT} decode -o "${OUT}" || _exit 1
+	cat "${PROTO_IN}" | ${CRIT} decode > "${OUT}" || _exit 1
+	${CRIT} decode -i "${PROTO_IN}" || _exit 1
+	${CRIT} decode -i "${PROTO_IN}" -o "${OUT}" || _exit 1
+	${CRIT} decode -i "${PROTO_IN}" > "${OUT}" || _exit 1
+	${CRIT} decode < "${PROTO_IN}" || _exit 1
+	${CRIT} decode -o "${OUT}" < "${PROTO_IN}" || _exit 1
+	${CRIT} decode < "${PROTO_IN}" > "${OUT}" || _exit 1
+
+	# proto in - json out encode -> should fail
+	cat "${PROTO_IN}" | ${CRIT} encode || true
+	cat "${PROTO_IN}" | ${CRIT} encode -o "${OUT}" || true
+	cat "${PROTO_IN}" | ${CRIT} encode > "${OUT}" || true
+	${CRIT} encode -i "${PROTO_IN}" || true
+	${CRIT} encode -i "${PROTO_IN}" -o "${OUT}" || true
+	${CRIT} encode -i "${PROTO_IN}" > "${OUT}" || true
+
+	# json in - proto out encode
+	cat "${JSON_IN}" | ${CRIT} encode || _exit 1
+	cat "${JSON_IN}" | ${CRIT} encode -o "${OUT}" || _exit 1
+	cat "${JSON_IN}" | ${CRIT} encode > "${OUT}" || _exit 1
+	${CRIT} encode -i "${JSON_IN}" || _exit 1
+	${CRIT} encode -i "${JSON_IN}" -o "${OUT}" || _exit 1
+	${CRIT} encode -i "${JSON_IN}" > "${OUT}" || _exit 1
+	${CRIT} encode < "${JSON_IN}" || _exit 1
+	${CRIT} encode -o "${OUT}" < "${JSON_IN}" || _exit 1
+	${CRIT} encode < "${JSON_IN}" > "${OUT}" || _exit 1
+
+	# json in - proto out decode -> should fail
+	cat "${JSON_IN}" | ${CRIT} decode || true
+	cat "${JSON_IN}" | ${CRIT} decode -o "${OUT}" || true
+	cat "${JSON_IN}" | ${CRIT} decode > "${OUT}" || true
+	${CRIT} decode -i "${JSON_IN}" || true
+	${CRIT} decode -i "${JSON_IN}" -o "${OUT}" || true
+	${CRIT} decode -i "${JSON_IN}" > "${OUT}" || true
+}
+
 gen_imgs
-run_test
+run_test1
+run_test2
diff --git a/test/others/env.sh b/test/others/env.sh
index 73369ad1b..b514e87d9 100755
--- a/test/others/env.sh
+++ b/test/others/env.sh
@@ -2,7 +2,16 @@
 
 CRIU=$(readlink -f `dirname ${BASH_SOURCE[0]}`/../../criu/criu)
 criu=$CRIU
-CRIT=$(readlink -f `dirname ${BASH_SOURCE[0]}`/../../crit/crit)
+if [ $(which python3) ]; then
+	PYTHON=python3
+elif [ $(which python2) ]; then
+	PYTHON=python2
+else
+	echo "FAIL: Neither python3 nor python2"
+	exit 1
+fi
+#export PYTHON
+CRIT=$(readlink -f `dirname ${BASH_SOURCE[0]}`/../../crit/crit-"${PYTHON}")
 crit=$CRIT
 CRIU_COREDUMP=$(readlink -f `dirname ${BASH_SOURCE[0]}`/../../criu-coredump/criu-coredump)
 criu_coredump=$CRIU_COREDUMP