Which command is used to bring a background job back to the foreground?

The command used to bring a background job back to the foreground is 'fg'. This command is specifically designed in Unix-like operating systems to resume a suspended job or to bring a background process into the foreground, allowing the user to interact with it directly in the terminal.

When a process is running in the background, it does not have direct control of the terminal, which means that the user can't provide input to it or see its output directly as they would with a foreground process. By using 'fg', the user can shift the background task to the foreground, allowing them to interact with it just like any other terminal command.

Other commands, such as 'bg', are used to resume jobs in the background rather than bringing them to the foreground. The 'jobs' command displays the list of current jobs, along with their status, but does not manipulate their execution. The 'start' command is not standard for job control in shell environments and therefore does not serve the purpose of managing job states in this context. Thus, 'fg' is the correct choice for this operation.