When editing a bash profile, which command would you use to apply the changes immediately?

Using the command source ~/.bash_profile applies the changes made to the bash profile immediately in the current shell session. When you modify ~/.bash_profile, those changes will not take effect in the current session until you either start a new terminal session or reload the profile. The source command (or its shorthand .) allows you to execute commands from the specified file within the current shell, effectively reloading the environment settings without needing to close and reopen the terminal.

For individuals who work with environment variables, aliases, or shell functions in their profile, this immediate effect is crucial for testing configurations or updates without interruption. By sourcing the profile, any new settings or changes made take place in real-time, ensuring a seamless workflow.

Other options would not provide the same immediate effect. Using bash ~/.bash_profile would run a new instance of the bash shell with the updated profile, but it wouldn't reflect those changes in the original shell session. The commands edit ~/.bash_profile and apply ~/.bash_profile do not exist in the context of applying or sourcing Bash configurations, and thus would not be valid commands for refreshing the session with the updated settings.