diff --git a/Dockerfile b/Dockerfile
index d9a5886..e72cd91 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -69,9 +69,11 @@ WORKDIR /root
 RUN set -e; \
   echo "Setting up prerequisites"; \
   yum makecache && yum install -yy bash; \
-  BASH_CMD="$(command -v bash 2>/dev/null|| true)"; \
-  [ -x "$BASH_CMD" ] && { rm -rf "/bin/sh" || true; } && ln -sf "$BASH_CMD" "/bin/sh" || true; \
-  [ -n "$BASH_CMD" ] && sed -i 's|root:x:.*|root:x:0:0:root:/root:'$BASH_CMD'|g' "/etc/passwd" || true
+  SH_CMD="$(which sh 2>/dev/null)"; \
+  BASH_CMD="$(which bash 2>/dev/null)"; \
+  [ -n "$BASH_CMD" ] && sed -i 's|root:x:.*|root:x:0:0:root:/root:'$BASH_CMD'|g' "/etc/passwd" || true; \
+  [ -x "$BASH_CMD" ] && [ "$SH_CMD" != "/bin/sh" ] && { rm -Rf "$SH_CMD";ln -s "$BASH_CMD" "$SH_CMD"; } || true; \
+  [ -x "$BASH_CMD" ] && [ ! -L "/bin/sh" ] && { rm -rf "/bin/sh" || true; } && ln -sf "$BASH_CMD" "/bin/sh" || true
 
 ENV SHELL="/bin/bash"
 SHELL [ "/bin/bash", "-c" ]
diff --git a/Dockerfile.8 b/Dockerfile.8
index 47c8436..c23e9c0 100644
--- a/Dockerfile.8
+++ b/Dockerfile.8
@@ -69,9 +69,11 @@ WORKDIR /root
 RUN set -e; \
   echo "Setting up prerequisites"; \
   yum makecache && yum install -yy bash; \
-  BASH_CMD="$(command -v bash 2>/dev/null|| true)"; \
-  [ -x "$BASH_CMD" ] && { rm -rf "/bin/sh" || true; } && ln -sf "$BASH_CMD" "/bin/sh" || true; \
-  [ -n "$BASH_CMD" ] && sed -i 's|root:x:.*|root:x:0:0:root:/root:'$BASH_CMD'|g' "/etc/passwd" || true
+  SH_CMD="$(which sh 2>/dev/null)"; \
+  BASH_CMD="$(which bash 2>/dev/null)"; \
+  [ -n "$BASH_CMD" ] && sed -i 's|root:x:.*|root:x:0:0:root:/root:'$BASH_CMD'|g' "/etc/passwd" || true; \
+  [ -x "$BASH_CMD" ] && [ "$SH_CMD" != "/bin/sh" ] && { rm -Rf "$SH_CMD";ln -s "$BASH_CMD" "$SH_CMD"; } || true; \
+  [ -x "$BASH_CMD" ] && [ ! -L "/bin/sh" ] && { rm -rf "/bin/sh" || true; } && ln -sf "$BASH_CMD" "/bin/sh" || true
 
 ENV SHELL="/bin/bash"
 SHELL [ "/bin/bash", "-c" ]
diff --git a/Dockerfile.9 b/Dockerfile.9
index 0cbb86b..32578a7 100644
--- a/Dockerfile.9
+++ b/Dockerfile.9
@@ -69,9 +69,11 @@ WORKDIR /root
 RUN set -e; \
   echo "Setting up prerequisites"; \
   yum makecache && yum install -yy bash; \
-  BASH_CMD="$(command -v bash 2>/dev/null|| true)"; \
-  [ -x "$BASH_CMD" ] && { rm -rf "/bin/sh" || true; } && ln -sf "$BASH_CMD" "/bin/sh" || true; \
-  [ -n "$BASH_CMD" ] && sed -i 's|root:x:.*|root:x:0:0:root:/root:'$BASH_CMD'|g' "/etc/passwd" || true
+  SH_CMD="$(which sh 2>/dev/null)"; \
+  BASH_CMD="$(which bash 2>/dev/null)"; \
+  [ -n "$BASH_CMD" ] && sed -i 's|root:x:.*|root:x:0:0:root:/root:'$BASH_CMD'|g' "/etc/passwd" || true; \
+  [ -x "$BASH_CMD" ] && [ "$SH_CMD" != "/bin/sh" ] && { rm -Rf "$SH_CMD";ln -s "$BASH_CMD" "$SH_CMD"; } || true; \
+  [ -x "$BASH_CMD" ] && [ ! -L "/bin/sh" ] && { rm -rf "/bin/sh" || true; } && ln -sf "$BASH_CMD" "/bin/sh" || true
 
 ENV SHELL="/bin/bash"
 SHELL [ "/bin/bash", "-c" ]