shell script to print number positive or negative

$ cat ppn.sh
# to print positive  or negative numbers
clear
echo " `tput cup 5 5` enter number:"
tput cup 5 30;read var
if [ $var -eq 0 ]
then
clear;tput cup 5 5;echo "zero"
elif [ $var -lt 0 ]
then
tput cup 7 5;echo "negative"
else
tput cup 7 5;echo "positive"
fi

echo "- - -" > /sys/class/scsi_host/hosth/scan explanation

echo "- - -" > /sys/class/scsi_host/hosth/scan

This procedure will add LUNs, but not remove them.

In this case,  three fields are

1) the channel number, 

2)SCSI target ID

3)LUN values are replaced by wildcards. 

Any combination of identifiers and wildcards is allowed, allowing you to make the command as specific or broad as needed. 

Ansible Plays and Play books

Ansible Plays and Play books
Plays maps hosts to tasks
A play can have multiple tasks
A play book can have multiple plays.
at HOME dir:-
[ansible@ansibleserver ~]$ cat .vimrc
autocmd FileType yaml setlocal ai ts=2 sw=2 et

[ansible@ansibleserver playbooks]$ cat firstplay.yaml
---
- name: first yaml file
  hosts: db
  vars_prompt:
  - name: "sitename"
    prompt: "what is new state name?"
  tasks:
  - debug: msg="new state name is {{sitename}}"
...
[ansible@ansibleserver playbooks]$ ansible-playbook firstplay.yaml
what is new state name?:

PLAY [first yaml file] ***************************************************************************************************************

TASK [Gathering Facts] ***************************************************************************************************************
ok: [10.25.12.10]

TASK [debug] *************************************************************************************************************************
ok: [10.25.12.10] => {
    "msg": "new state name is TS"
}

PLAY RECAP ***************************************************************************************************************************
10.25.12.10                : ok=2    changed=0    unreachable=0    failed=0

ANSIBLE modules

Ansible Modules:-
There are three types of modules existed
1)Core Modules : these are built in modules
2)Extra Modules: these are third party modules
3) Deprecated Modules: these are no longer available.

to display:
$ansible -doc     -l
$ansible-doc  ping
$ansible host1 -m setup|more
$ansible host1   -m setup -a "filter=ansible_mounts"

How to use specific Python version as interpreter in Ansible?

Ansible needs 2.X version as interpreter.
we can declare required python version in inventory file
[ansible@ansibleserver ~]$ cat inventory_python
10.25.12.10 ansible_python_interpreter=/usr/bin/python2.7

[ansible@ansibleserver ~]$ ansible all -i inventory_python -m ping -u ansible
10.25.12.10 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

Note:- if version not existed throws error.

Ansible inventory

inventory Features:-
1)Behavioral Parameters
2)Groups
3)Group of Groups
4)Assign Variables
5)Scaling Out using multiple files
6)Static/Dynamic
examples:-
cat /etc/ansible/ansible.cfg|grep -i inventory
[ansible@ansibleserver ~]$ cat /etc/ansible/ansible.cfg |grep -i inventory
inventory      = /etc/ansible/hosts

#cat /etc/ansible/hosts
10.25.12.11
10.25.12.10
10.25.12.13
[db]
10.25.12.10

[web]
10.25.12.13

[datacenter:children]
db
web

To know List of Ansible hosts:-
[ansible@ansibleserver ~]$ ansible all --list-hosts
  hosts (3):
    10.25.12.10
    10.25.12.11
    10.25.12.13
[ansible@ansibleserver ~]$ ansible db --list-hosts
  hosts (1):
    10.25.12.10
[ansible@ansibleserver ~]$ ansible web --list-hosts
  hosts (1):
    10.25.12.13
[ansible@ansibleserver ~]$ ansible datacenter --list-hosts
  hosts (2):
    10.25.12.10
    10.25.12.13

=================
we can create local inventories as well.
ex:-
[ansible@ansibleserver ~]$ cat inventory
10.25.12.13 ansible_ssh_user=ansible ansible_ssh_pass=ansible
[ansible@ansibleserver ~]$ ansible all -i inventory -m ping
10.25.12.13 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
[ansible@ansibleserver ~]$ ansible all -i inventory -a 'df -h'
10.25.12.13 | CHANGED | rc=0 >>
Filesystem             Size  Used Avail Use% Mounted on
/dev/mapper/rhel-root   18G  2.9G   15G  17% /
devtmpfs               481M     0  481M   0% /dev
tmpfs                  490M     0  490M   0% /dev/shm
tmpfs                  490M  6.9M  484M   2% /run
tmpfs                  490M     0  490M   0% /sys/fs/cgroup
/dev/sda1              497M  119M  379M  24% /boot

[ansible@ansibleserver ~]$ ansible all -i inventory -a 'hostname'
10.25.12.13 | CHANGED | rc=0 >>
clinet.example.com

==============
[ansible@ansibleserver ~]$ cat inventory
10.25.12.13 ansible_ssh_user=ansible ansible_ssh_pass=ansible
10.25.12.11 ansible_ssh_user=ansible ansible_ssh_pass=ansible ansible_python_interpreter=/usr/bin/python
[ansible@ansibleserver ~]$ ansible all -i inventory -a 'hostname'
10.25.12.11 | CHANGED | rc=0 >>
yumserver.example.com

10.25.12.13 | CHANGED | rc=0 >>
clinet.example.com

==============
Declaring inventory Varibles:-
[ansible@ansibleserver ~]$ cat inventory
10.25.12.13 ansible_ssh_user=ansible ansible_ssh_pass=ansible
10.25.12.11 ansible_ssh_user=ansible ansible_ssh_pass=ansible ansible_python_interpreter=/usr/bin/python
[db]
10.25.12.11

[web]
10.25.12.13

[datacenter:children]
db
web

[datacenter:vars]
ansible_ssh_user=student
ansible_ssh_pass=student
[ansible@ansibleserver ~]$

[ansible@ansibleserver ~]$ ansible datacenter -i inventory -m ping
10.25.12.11 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
10.25.12.13 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

ANSIBLE Architecture

1) Ansible Architecture:-
inventory+modules=Ansible playbook
Ansible Playbook --> Ansible config -->PYTHON --> SSH --> multiple clients