The "fg" command is a command line tool used in Unix-like operating systems to bring a background process to the foreground. When a process is running in the background, it is detached from the terminal and continues executing without any user interaction. The "fg" command allows the process to be moved back to the foreground, where it can receive input and produce output visible to the user.
Typically, the fg command is used alongside the job control feature provided by Unix-like shells. When a process is running in the background, it is assigned a job number. The "fg" command can either take no arguments, in which case it brings the most recently backgrounded process to the foreground, or it can take a job number or a process ID as an argument to specify which process to bring to the foreground.
The typical syntax for using the "fg" command is:
fg [job number | process ID]
Once the process is brought to the foreground, it becomes the active process on the terminal, and the user can interact with it using standard input/output.