Which command allows executing a script while modifying environment variables without affecting the system environment?

The command that allows executing a script while modifying environment variables without affecting the system environment is the "env" command. This command creates a fresh environment to run the specified command or script. When you use "env" followed by a command, it sets up the environment variables specifically for that execution and does not change the current user's environment or any global settings.

For example, you can use "env VAR=value ./script.sh" to run "script.sh" with "VAR" set to "value". The original environment variables remain untouched, thus providing a controlled environment for the script to execute. This is particularly useful for testing scripts that require specific environment setups without permanently altering your session or system environment.

The other options reference commands with different functionalities. For instance, "export" is used to set environment variables for the current shell and its subprocesses, which would affect the system environment. "printenv" displays the current environment variables but does not modify them, and "set" can change shell options and values but does not isolate the environment like "env" does.