diff --git a/install.sh b/install.sh
index 9004176e9a..ca8a51bd69 100644
--- a/install.sh
+++ b/install.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 # run with PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true sh install.sh if chrome is already installed
 sh synapse/install.sh
 sh riot/install.sh
diff --git a/riot/install.sh b/riot/install.sh
index 8a8761b705..d9cc7292f0 100644
--- a/riot/install.sh
+++ b/riot/install.sh
@@ -1,7 +1,8 @@
+#!/bin/bash
 RIOT_BRANCH=master
 
 BASE_DIR=$(readlink -f $(dirname $0))
-if [[ -d $BASE_DIR/riot-web ]]; then
+if [ -d $BASE_DIR/riot-web ]; then
 	echo "riot is already installed"
 	exit
 fi
diff --git a/riot/start.sh b/riot/start.sh
index ec3e5b32bc..3892a80a48 100644
--- a/riot/start.sh
+++ b/riot/start.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 PORT=8080
 echo "running riot on http://localhost:$PORT..."
 BASE_DIR=$(readlink -f $(dirname $0))
diff --git a/riot/stop.sh b/riot/stop.sh
index 40695c749c..a3dc722e58 100644
--- a/riot/stop.sh
+++ b/riot/stop.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 BASE_DIR=$(readlink -f $(dirname $0))
 cd $BASE_DIR
 PIDFILE=riot.pid
diff --git a/run.sh b/run.sh
index d4d4261430..ae073d2ba9 100644
--- a/run.sh
+++ b/run.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 sh synapse/start.sh
 sh riot/start.sh
 node start.js
diff --git a/synapse/install.sh b/synapse/install.sh
index 661c98ecd5..8260f208c2 100644
--- a/synapse/install.sh
+++ b/synapse/install.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 # config
 SYNAPSE_BRANCH=master
 INSTALLATION_NAME=consent
@@ -7,7 +8,7 @@ PORT=8008
 # set current directory to script directory
 BASE_DIR=$(readlink -f $(dirname $0))
 
-if [[ -d $BASE_DIR/$SERVER_DIR ]]; then
+if [ -d $BASE_DIR/$SERVER_DIR ]; then
 	echo "synapse is already installed"
 	exit
 fi
diff --git a/synapse/start.sh b/synapse/start.sh
index f7af6ac0f7..785909a0b1 100644
--- a/synapse/start.sh
+++ b/synapse/start.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 BASE_DIR=$(readlink -f $(dirname $0))
 cd $BASE_DIR
 cd installations/consent
diff --git a/synapse/stop.sh b/synapse/stop.sh
index ff9b004533..d83ddd0e4a 100644
--- a/synapse/stop.sh
+++ b/synapse/stop.sh
@@ -1,3 +1,4 @@
+#!/bin/bash
 BASE_DIR=$(readlink -f $(dirname $0))
 cd $BASE_DIR
 cd installations/consent