Script has 4 options:

1. Encode to Base64.
2. Decode from Base64.
3. Encode strings from a txt file.
4. Decode Base64 encoding from a txt file.

Option 1:

Option 2:

Option 3:

Option 4:

Open the terminal and enter the below command to change permissions on the script.

chmod +x Bash_Base64.sh

Execute ./Bash_Base64.sh

Tested on Ubuntu OS