Passing password from vault to unix script

I'm new to ansible.

I'm trying to pick the passwords out of a vault file and pass them to a unix script.

Created oem_vault.yml under group_vars/all

ansible-vault edit groups_vars/all/oem.yml

oem_vault:
user: sysman
password: XXXXXXXXXX

2. create playbook

cat tgt-blackout-oem-on.yml

#!/usr/bin/env ansible-playbook
---

 - name: Turn blackout on for target clone
   hosts: hostapp01
   any_errors_fatal: true
   remote_user: ansible
   become: yes
   become_user: oracle
   roles:
      - oraoem-blackout-on
   vars_files:
      - groups_vars/all/oem.yml

3.create roles and tasks

cd roles/oraoem-blackout-on/

cat main.yml

---
- name: Setting static variables
  set_fact:
    dest: /home/oracle/ansible

- name: Copy the blackout script for the target node
  copy:
    src: "{{ item }}"
    dest: /home/oracle/ansible
    owner: oracle
    group: oinstall
    mode: 0700
  with_items:
    - oem_blackout_on.sh

- name: Performing blackout on
  shell: "cd {{ dest }}; {{ dest }}/oem_blackout_on.sh {{ oem_vault.user }} {{ oem_vault.password }}"
  register: oem_on
  ignore_errors: no
- debug: var=oem_on.stderr_lines
  tags:
    - oem_on

Running execution output:

TASK [oraoem-blackout-on : Performing blackout on]
 *********************************************************************    
fatal: [hostapp01]: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: 'None' has no attribute 'sysman'\n\nThe error appears to be in 'roles/oraoem-blackout-on/tasks/main.yml': line 20, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- name: Performing blackout on\n  ^ here\n"}

I was expecting it to pick up the username and password and pass it to the unix script which then gets executed on the remote server

The name of the directory groups_vars is wrong. The correct name is group_vars

Given the file

shell> cat group_vars/all/oem.yml 
oem_vault:
user: sysman
password: XXXXXXXXXX

the playbook

shell> cat pb.yml
- hosts: localhost
  tasks:
    - debug:
        var: password

works as expected

shell> ansible-playbook pb.yml 

PLAY [localhost] *****************************************************************************

TASK [debug] *********************************************************************************
ok: [localhost] => 
  password: XXXXXXXXXX

PLAY RECAP ***********************************************************************************
localhost: ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

shell> ansible-vault encrypt group_vars/all/oem.yml