Shell script to make site https using certbot and nginx

Question

I know how to install ssl certificate using command-line. But i need a shell script this time to do this task.

Generally while doing this manually i first execute the fowllowing:-

sudo apt-get install certbot python-certbot-nginx

By executing the above i will be asked to continue or not?[Y/n]. I will enter 'Y'.Then i will execute the following command

sudo certbot --nginx

Executing the above will ask me to answer the following steps in ordered way:

1. Enter email address (used for urgent renewal and security notices) (Enter 'c' to cancel).
2. Agreement to Terms and Service [ (A)gree/(C)ancel: A ]
3. Consent to share development news and campaigns to my email address. [(Y)es/(N)o: N]
4. Which names would i like to activate HTTPS for? [Select the appropriate numbers separated by commas and/or spaces, or leave input blank to select all options shown (Enter 'c' to cancel): blank]
5. Redirection from http to https [Select the appropriate number [1-2] then [enter] (press 'c' to cancel): 2 ]

After doing all this steps https will be enabled. Now i need to do these things done programatically by shell file.I have figured out to install certbot and python-certbot-nginx using this

sudo apt-get install certbot python-certbot-nginx -y

But i do not know how to proceed further as i have never worked with shell scripts

PS: I am providing a sample result when i execute sudo certbot --nginx and enter details by myself.

sudo certbot --nginx
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator nginx, Installer nginx
Enter email address (used for urgent renewal and security notices) (Enter 'c' to
cancel): [email protected]

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Please read the Terms of Service at
https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf. You must
agree in order to register with the ACME server at
https://acme-v02.api.letsencrypt.org/directory
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
(A)gree/(C)ancel: A

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Would you be willing to share your email address with the Electronic Frontier
Foundation, a founding partner of the Let's Encrypt project and the non-profit
organization that develops Certbot? We'd like to send you email about our work
encrypting the web, EFF news, campaigns, and ways to support digital freedom.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
(Y)es/(N)o: N

Which names would you like to activate HTTPS for?
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
1: example.com
2: www.example.com
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Select the appropriate numbers separated by commas and/or spaces, or leave input
blank to select all options shown (Enter 'c' to cancel):
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for example.com
http-01 challenge for www.example.com
Waiting for verification...
Cleaning up challenges
Deploying Certificate to VirtualHost /etc/nginx/sites-enabled/demowebsite.conf
Deploying Certificate to VirtualHost /etc/nginx/sites-enabled/demowebsite.conf

Please choose whether or not to redirect HTTP traffic to HTTPS, removing HTTP access.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
1: No redirect - Make no further changes to the webserver configuration.
2: Redirect - Make all requests redirect to secure HTTPS access. Choose this for
new sites, or if you're confident your site works on HTTPS. You can undo this
change by editing your web server's configuration.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Select the appropriate number [1-2] then [enter] (press 'c' to cancel): 2
Redirecting all traffic on port 80 to ssl in /etc/nginx/sites-enabled/demowebsite.conf
Redirecting all traffic on port 80 to ssl in /etc/nginx/sites-enabled/demowebsite.conf

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Congratulations! You have successfully enabled
https://example.com and
https://www.example.com

You should test your configuration at:
https://www.ssllabs.com/ssltest/analyze.html?d=example.com
https://www.ssllabs.com/ssltest/analyze.html?d=www.example.com
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IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/example.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/example.com/privkey.pem
   Your cert will expire on 2020-01-28. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot again
   with the "certonly" option. To non-interactively renew *all* of
   your certificates, run "certbot renew"
 - Your account credentials have been saved in your Certbot
   configuration directory at /etc/letsencrypt. You should make a
   secure backup of this folder now. This configuration directory will
   also contain certificates and private keys obtained by Certbot so
   making regular backups of this folder is ideal.
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

Answer 1

Though i am very late here but finally i did as suggested by @JohnHanley in the comments. I went through the documentation and here is what i needed to execute the above mentioned steps in the question by command line.

run            Obtain & install a certificate in your current webserver

-n             Run without ever asking for user input. This may
               require additional command line flags; the client will
               try to explain which ones are required if it finds one
               missing (default: False)

--nginx        Obtain and install certificates using Nginx (default:False)


-d             Domain names to apply. For multiple domains you can
               use multiple -d flags or enter a comma separated list
               of domains as a parameter. The first domain provided
               will be the subject CN of the certificate, and all
               domains will be Subject Alternative Names on the
               certificate. The first domain will also be used in
               some software user interfaces and as the file paths
               for the certificate and related material unless
               otherwise specified or you already have a certificate
               with the same name. In the case of a name collision it
               will append a number like 0001 to the file path name.


-m             Email used for registration and recovery contact. Use
               comma to register multiple emails, ex:
               [email protected],[email protected]. (default: Ask).

--redirect     Automatically redirect all HTTP traffic to HTTPS for
               the newly authenticated vhost. (default: Ask)

--agree-tos    Agree to the ACME server's Subscriber Agreement

So the final command that i executed is below

certbot run -n --nginx --agree-tos -d example.com,www.example.com -m [email protected] --redirect