摘要： When you run a program from the shell prompt, stdin is connected to your keyboard, and stdout and stderr are connected to your monitor.when you run a program in the background,the input is disconnected(standard input would be connected to the empty file /dev/null), but the output connections do not 阅读全文

摘要： You use an interactive shell when you enter commands at the shell prompt; you use a non-interactive shell when you run a shell script.Whenever you log in, the shell that starts is called a LOGIN SHELL. All other interactive shells are called NON-LOGIN SHELLSThe distinction is important because initi 阅读全文