Handling Issues in Migration

Fix "non-existent config entity name returned by FieldStorageConfigInterface::getBundles()"
Normally it will show that a field belongs to a non existing bundle for a node, comment etcetra in log post migration.
Solving a field that does not belong to non existent bundle in a node, example, field_agenda present in a non existent bundle makemeeting of node type

Optimizing Images using command line

The images uploaded by users may not be of ideal size and may require compression to manage server space. There are some tools available for compressing JPG and PNG files.
Please note that the owner changes to the current username for the file after compression. Please remember to change ownership if required of the file or per folder post compression.

jpegoptim :
Optimize a jpg image with the same name

jpegoptim image.jpg

Optimize all jpg images in a folder

Managing Flag Development In D8

Technologies: 

Check if an entity has been flagged:

/**@var \Drupal\flag\FlagService $flag_service */
$flag_service = \Drupal::service('flag');
$flag = $flag_service->getFlagById($flag_id);
return $flag->isFlagged($node);

Get all flagging users for an entity and flag:

$flagging = $flag_service->getFlaggingUsers($entity, $flag); //  $flag is optional

Flag an entity:

SSL Certificate Using Let's Encrypt for Ubuntu

Automated creation, renewing of certificates is provided by software called certbot.

To view a list of the certificates Certbot knows about, run the certificates subcommand:

$> certbot certificates

Deleting certificates

$> certbot delete --cert-name example.com

Install Certificates Using Apache

Git Management

Technologies: 

Associating your local repo to a repo in third party Git repository, say Bitbucket.

Step 1: Switch to your repository's directory

cd /path/to/your/repo

Step 2: Connect your existing repository to Bitbucket

Server Certification

Technologies: 

Checking Passphrase for private key:  openssl rsa -check -in keyfilename
Changing Passphrase: openssl rsa -des3 -in keyfilename -out newkeyfilename

Installing or trusting certificates:
Extensions .crt, .pem and .cer are interchangeable, just change the file name extension, they have the same form. Try this:

sudo cp mycert.cer /usr/share/ca-certificates/mycert.pem
sudo dpkg-reconfigure ca-certificates
sudo update-ca-certificates

Getting the RSA public and private key from conf file.