title: Unknown Instruction ln Docker File in RUN
body: <p>Hi Here is my Docker File. I getting an Error while Installing Maven it's not able to find "ln -s" Soft Link Command. Please Help me with this.</p>
  
  <pre><code># We first will give the base image details for the tag "FROM" OS:Version
  FROM centos:latest
  #who will maintain the image 
  MAINTAINER XYZ &lt;XYZ@gmail.com&gt;
  
  
  RUN yum install -y httpd curl sed grep egrep fgrep wget git net-tools zip unzip which source openssh-server
  
  #JAVA INSTALLATION
  ADD http://www.mediafire.com/file/177sevky311fbdh/jdk-8u144-linux-x64.rpm / 
  RUN rpm -ivh jdk-8u144-linux-x64.rpm 
  ENV JAVA_HOME="/usr/java/jdk1.8.0_144"  
  ENV JRE_HOME="/usr/java/jdk1.8.0_144/jre"
  
  #MAVEN INSTALLATION
  ADD https://www.mediafire.com/folder/6b0t6el85gtof/maven /
  RUN mv /maven /opt/maven
      ln -s /opt/maven/bin/mvn /usr/bin/mvn &amp;&amp; \
      wget http://www.mediafire.com/file/gpg2arhygj0a0wy/maven.sh &amp;&amp; \
      mv /maven.sh /etc/profile.d &amp;&amp; \
      chmod 755 /etc/profile.d/maven.sh
  
  
  RUN cp /etc/ssh/sshd_config /etc/ssh/sshd_config.original &amp;&amp; \
      chmod a-w /etc/ssh/sshd_config.original &amp;&amp; \
      mkdir /var/run/sshd &amp;&amp; \
      echo 'root:screencast' | chpasswd &amp;&amp; \
      sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config
  
  CMD ["/usr/sbin/sshd, "-D"]
  EXPOSE 22 
  </code></pre>