I have this bitbucket pipeline:

image: ubuntu:latest

pipelines:
  branches:
    master:
      - step:
          name: Upload
          script:
            - apt-get update && apt-get install -y openssh-client jq curl
            - cat /opt/atlassian/pipelines/agent/ssh/id_rsa >> ec2_private_key.pem
            - chmod 600 ec2_private_key.pem
            - echo "Fetching modified files from Bitbucket API using diff endpoint"
            - |
              curl -s -H "Authorization: Bearer $API_TOKEN_BEARER" 
              "https://api.bitbucket.org/2.0/repositories/$BITBUCKET_REPO_FULL_NAME/commits/master" 
              | jq -r '.values[0].hash' > latest_commit.txt
            - COMMIT_HASH=$(cat latest_commit.txt)
            - |
              curl -s -H "Authorization: Bearer $API_TOKEN_BEARER" 
              "https://api.bitbucket.org/2.0/repositories/$BITBUCKET_REPO_FULL_NAME/diff/$COMMIT_HASH" 
              | grep '^+++ b' | awk '{print $2}' | sed 's/^b///' > modified_files.txt
            - echo "Modified files:"
            - cat modified_files.txt
            - while IFS= read -r file; do
                scp -i ec2_private_key.pem -o StrictHostKeyChecking=no -r "$file" ubuntu@$EC2_HOST:$PATH"$file";
              done < modified_files.txt
            - ssh -i ec2_private_key.pem -o StrictHostKeyChecking=no ubuntu@$EC2_HOST "cd $PATH && sudo docker-compose up --build -d"

Which is very similar to another pipeline I have in another repository and already works. However, it seems that the image is not correctly installed when the pipeline is executed. In the build set up, I get this error:

Images used:
build : docker.io/library/ubuntu@sha256:
bash: dircolors: command not found

And in the apt-get line I get this error:

• apt-get update && apt-get install -y openssh-client jq curl
  bash: apt-get: command not found