If you use the AWS CLI tool for your operations and application implementation, it's important to note that the CLI searches for credentials and configuration data in a specific hierarchical order.
Command Line Options
For example: using options like "--profile", "--region", "--output" etc...
If the necessary data is not found through command line options, the CLI will check for environmental variables.
Environmental Variables
AWS_ACCESS_KEY_ID
AWS_SECRET_ACCESS_KEY
AWS_SESSION_TOKEN
AWS_DEFAULT_REGION
... and so on. If the data is still not found, the CLI will look for it in the CLI credentials file, which can be found at the following locations:
For Linux: ~/.aws/credentials
For Windows: C:\Users\<user-name>\.aws\credentials
Finally, if the data is still not found, the CLI will search for it in the CLI configuration file, which can be found at the following locations:
For Linux: ~/.aws/config
For Windows: C:\Users<user-name>.aws\config