Which command is used to terminate a running process in Linux?

The command used to terminate a running process in Linux is "kill." This command sends a signal to a specified process to request its termination. By default, it sends the SIGTERM signal, which instructs the process to terminate gracefully, allowing it to perform necessary cleanup. The "kill" command can also be used with different signals to control the behavior of processes. For example, using SIGKILL, which immediately stops a process without allowing it to perform cleanup, is also possible with "kill."

The other provided options do not serve this purpose in the context of Linux command-line operations. "stop" and "end" do not exist as standalone commands for process termination; they may be confused with concepts from different contexts or environments. "exit" is a command used to terminate a shell session but not to end a running process explicitly. Thus, "kill" is the appropriate and correct command for the task specified in the question.