title: How to force Docker for a clean build of an image
body: <p>I have build a Docker image from a Docker file using the below command.</p>
  
  <pre><code>$ docker build -t u12_core -f u12_core .
  </code></pre>
  
  <p>When I am trying to rebuild it with the same command, it's using the build cache like:</p>
  
  <pre><code>Step 1 : FROM ubuntu:12.04
   ---&gt; eb965dfb09d2
  Step 2 : MAINTAINER Pavan Gupta &lt;pavan.gupta@gmail.com&gt;
   ---&gt; Using cache
   ---&gt; 4354ccf9dcd8
  Step 3 : RUN apt-get update
   ---&gt; Using cache
   ---&gt; bcbca2fcf204
  Step 4 : RUN apt-get install -y openjdk-7-jdk
   ---&gt; Using cache
   ---&gt; 103f1a261d44
  Step 5 : RUN apt-get install -y openssh-server
   ---&gt; Using cache
   ---&gt; dde41f8d0904
  Step 6 : RUN apt-get install -y git-core
   ---&gt; Using cache
   ---&gt; 9be002f08b6a
  Step 7 : RUN apt-get install -y build-essential
   ---&gt; Using cache
   ---&gt; a752fd73a698
  Step 8 : RUN apt-get install -y logrotate
   ---&gt; Using cache
   ---&gt; 93bca09b509d
  Step 9 : RUN apt-get install -y lsb-release
   ---&gt; Using cache
   ---&gt; fd4d10cf18bc
  Step 10 : RUN mkdir /var/run/sshd
   ---&gt; Using cache
   ---&gt; 63b4ecc39ff0
  Step 11 : RUN echo 'root:root' | chpasswd
   ---&gt; Using cache
   ---&gt; 9532e31518a6
  Step 12 : RUN sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config
   ---&gt; Using cache
   ---&gt; 47d1660bd544
  Step 13 : RUN sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd
   ---&gt; Using cache
   ---&gt; d1f97f1c52f7
  Step 14 : RUN wget -O aerospike.tgz 'http://aerospike.com/download/server/latest/artifact/ubuntu12'
   ---&gt; Using cache
   ---&gt; bd7dde7a98b9
  Step 15 : RUN tar -xvf aerospike.tgz
   ---&gt; Using cache
   ---&gt; 54adaa09921f
  Step 16 : RUN dpkg -i aerospike-server-community-*/*.deb
   ---&gt; Using cache
   ---&gt; 11aba013eea5
  Step 17 : EXPOSE 22 3000 3001 3002 3003
   ---&gt; Using cache
   ---&gt; e33aaa78a931
  Step 18 : CMD /usr/sbin/sshd -D
   ---&gt; Using cache
   ---&gt; 25f5fe70fa84
  Successfully built 25f5fe70fa84
  </code></pre>
  
  <p>The cache shows that aerospike is installed. However, I don't find it inside containers spawn from this image, so I want to rebuild this image without using the cache. How can I force Docker to rebuild a clean image without the cache?</p>