What symbol is used to run a file as an absolute path?

To run a file as an absolute path in a Unix-like operating system, the correct option is the symbol indicating the current directory: './'. This means that the system will look for the executable file in the current working directory. Using './' in front of a command tells the shell to execute the file that is located in your current directory, which is essential when the current directory is not included in the system’s PATH environment variable.

The other symbols serve different purposes. For instance, a single slash '/' represents the root directory, which is the starting point for absolute file paths. The tilde '~' is used to denote the home directory of the current user, which provides a shortcut to access files in that specific folder. The '#' symbol typically signifies the start of a comment in shell scripts and does not have a function in directly running executables or scripts.

Thus, './' is the accurate choice for executing files from the current directory as an absolute path.