diff --git a/docker/torch1.12.1-cuda11.3.dockerfile b/docker/torch1.12.1-cuda11.3.dockerfile
index 4ac126348..c5e252abb 100644
--- a/docker/torch1.12.1-cuda11.3.dockerfile
+++ b/docker/torch1.12.1-cuda11.3.dockerfile
@@ -15,8 +15,8 @@ LABEL github_repo="https://github.com/k2-fsa/icefall"
 
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
-		    curl \
-	      vim \
+        curl \
+        vim \
     		libssl-dev \
         autoconf \
         automake \
@@ -54,11 +54,9 @@ RUN pip install --no-cache-dir \
       dill
 
 RUN git clone https://github.com/k2-fsa/icefall /workspace/icefall && \
-	cd /workspace/icefall && \
-	pip install --no-cache-dir -r requirements.txt
+    cd /workspace/icefall && \
+    pip install --no-cache-dir -r requirements.txt
 
 ENV PYTHONPATH /workspace/icefall:$PYTHONPATH
 
 WORKDIR /workspace/icefall
-
-
diff --git a/docker/torch1.13.0-cuda11.6.dockerfile b/docker/torch1.13.0-cuda11.6.dockerfile
index 4c1b216b0..bcbf8b599 100644
--- a/docker/torch1.13.0-cuda11.6.dockerfile
+++ b/docker/torch1.13.0-cuda11.6.dockerfile
@@ -15,8 +15,8 @@ LABEL github_repo="https://github.com/k2-fsa/icefall"
 
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
-		    curl \
-	      vim \
+        curl \
+        vim \
     		libssl-dev \
         autoconf \
         automake \
@@ -54,12 +54,11 @@ RUN pip install --no-cache-dir \
       dill
 
 RUN git clone https://github.com/k2-fsa/icefall /workspace/icefall && \
-	cd /workspace/icefall && \
-	pip install --no-cache-dir -r requirements.txt
+    cd /workspace/icefall && \
+    pip install --no-cache-dir -r requirements.txt
 
 ENV PYTHONPATH /workspace/icefall:$PYTHONPATH
 
 ENV LD_LIBRARY_PATH /opt/conda/lib/stubs:$LD_LIBRARY_PATH
 
 WORKDIR /workspace/icefall
-
diff --git a/docker/torch1.9.0-cuda10.2.dockerfile b/docker/torch1.9.0-cuda10.2.dockerfile
index a3b7d6fb1..7553fcf86 100644
--- a/docker/torch1.9.0-cuda10.2.dockerfile
+++ b/docker/torch1.9.0-cuda10.2.dockerfile
@@ -15,8 +15,8 @@ LABEL github_repo="https://github.com/k2-fsa/icefall"
 
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
-		    curl \
-	      vim \
+        curl \
+        vim \
     		libssl-dev \
         autoconf \
         automake \
@@ -54,11 +54,9 @@ RUN pip install --no-cache-dir \
       dill
 
 RUN git clone https://github.com/k2-fsa/icefall /workspace/icefall && \
-	cd /workspace/icefall && \
-	pip install --no-cache-dir -r requirements.txt
+    cd /workspace/icefall && \
+    pip install --no-cache-dir -r requirements.txt
 
 ENV PYTHONPATH /workspace/icefall:$PYTHONPATH
 
 WORKDIR /workspace/icefall
-
-
diff --git a/docker/torch2.0.0-cuda11.7.dockerfile b/docker/torch2.0.0-cuda11.7.dockerfile
index 633f44a07..c11c0bd67 100644
--- a/docker/torch2.0.0-cuda11.7.dockerfile
+++ b/docker/torch2.0.0-cuda11.7.dockerfile
@@ -15,8 +15,8 @@ LABEL github_repo="https://github.com/k2-fsa/icefall"
 
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
-		    curl \
-	      vim \
+        curl \
+        vim \
     		libssl-dev \
         autoconf \
         automake \
@@ -54,11 +54,9 @@ RUN pip install --no-cache-dir \
       dill
 
 RUN git clone https://github.com/k2-fsa/icefall /workspace/icefall && \
-	cd /workspace/icefall && \
-	pip install --no-cache-dir -r requirements.txt
+    cd /workspace/icefall && \
+    pip install --no-cache-dir -r requirements.txt
 
 ENV PYTHONPATH /workspace/icefall:$PYTHONPATH
 
 WORKDIR /workspace/icefall
-
-