How to force Docker for a clean build of an image
<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>