source

"source" is a command line tool commonly found in Unix-based operating systems like Linux and macOS.

The "source" command is used to read and execute commands from a specified file within the current shell environment.

It is primarily used to load script files that contain variables, functions, and shell settings into the current shell.

By using the "source" command, the script file's content is executed as if it were typed directly into the shell prompt.

Typically, the syntax for using "source" is 'source filename' or the shorthand version '. filename'.

The use of "source" instead of simply executing the file allows the changes to persist in the current shell environment.

The "source" command is commonly used when working with configuration files or when modifying the behavior of the current shell session.

One of the main advantages of using the "source" command is that it enables the sharing of environment variables and functions between different shell scripts and the main shell.

The "source" command is heavily used in shell scripting and is often employed to set up the environment for various software tools or customize the behavior of the shell.

Overall, "source" is a valuable tool for dynamically loading and executing shell scripts directly in the current shell environment, allowing for seamless integration and customization of the command line.