title: GITLAB CI Error loading key "/dev/fd/63": invalid format ERROR: Job failed: exit code 1
body: <p>Here is my code  giltlab-ci.yml :</p>
  
  <pre><code> before_script:
    ##
    ## Install ssh-agent if not already installed, it is required by Docker.
    ## (change apt-get to yum if you use an RPM-based image)
    ##
    - 'which ssh-agent || ( apt-get update -y &amp;&amp; apt-get install openssh-client -y )'
  
    ##
    ## Run ssh-agent (inside the build environment)
    ##
    - eval $(ssh-agent -s)
    ##
    ## Add the SSH key stored in SSH_PRIVATE_KEY variable to the agent store
    ## We're using tr to fix line endings which makes ed25519 keys work
    ## without extra base64 encoding.
    ## https://gitlab.com/gitlab-examples/ssh-private-key/issues/1#note_48526556
    ##
    - mkdir -p ~/.ssh
    #- echo -n "$PROJECT_SSH_KEY" | ssh-add - &gt;/dev/null
    - echo "$PROJECT_SSH_KEY"
    - ssh-add &lt;(echo "$PROJECT_SSH_KEY")
    - '[[ -f /.dockerenv ]] &amp;&amp; echo -e "Host *\n\tStrictHostKeyChecking no\n\n" &gt; ~/.ssh/config'
        ##
    ## Create the SSH directory and give it the right permissions
    ##
    - mkdir -p ~/.ssh
    - chmod 700 ~/.ssh
  
    ##
    ## Optionally, if you will be using any Git commands, set the user name and
    ## and email.
    ##
    #- git config --global user.email "user@example.com"
    #- git config --global user.name "User name"
  </code></pre>
  
  <p>I get  this out put</p>
  
  <blockquote>
    <p>Running with gitlab-runner 11.8.0 (4745a6f3)
          on Allence-Tunisie-docker-runner sH47eTgb
        Using Docker executor with image ntfactory/ci-tool:0.0.2 ...
        Pulling docker image ntfactory/ci-tool:0.0.2 ...
        Using docker image sha256:7fe7b170806f6846271eec23b41c4f79202777f62c0d7a32165dc41722900979
    for ntfactory/ci-tool:0.0.2 ...
        Running on runner-sH47eTgb-project-11060727-concurrent-0 via a732493b4b94...
        Cloning repository...
        Cloning into '/builds/allence-tunisie/e-formation'...
        Checking out 0a6b48ef as feat/gitlab-ci...
        Skipping Git submodules setup
        Checking cache for default...
        No URL provided, cache will not be downloaded from shared cache server. Instead a local version of cache will be extracted. 
        Successfully extracted cache
        $ which ssh-agent || ( apt-get update -y &amp;&amp; apt-get install openssh-client -y )
        /usr/bin/ssh-agent
        $ eval $(ssh-agent -s)
        Agent pid 12
        $ mkdir -p ~/.ssh
        $ echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add - > /dev/null
        Error loading key "(stdin)": invalid format
        ERROR: Job failed: exit code 1</p>
  </blockquote>
  
  <p>even though i tried  - echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add
  - > /dev/null   i get  this error</p>
  
  <blockquote>
    <p>Error loading key "(stdin)": invalid format</p>
  </blockquote>