Standard streams are a fundamental concept in computer programming and operating systems. They represent the basic input and output channels that programs use to communicate with their environment. In most operating systems, including Unix-like systems and Windows, there are three standard streams:
Standard Input (stdin): This is the stream through which a program receives input from the user or from another program. By default, the standard input is usually connected to the keyboard, but it can be redirected to read input from files or other sources.
Standard Output (stdout): This is the stream through which a program sends its regular output. By default, the standard output is connected to the display screen or terminal, allowing the program’s output to be seen by the user. Like standard input, it can be redirected to write output to files or other destinations.
Standard Error (stderr): This stream is used for error messages and diagnostic output that a program generates. It’s also connected to the display screen or terminal by default. Redirecting stderr allows separation of error messages from regular output, which can be useful for debugging and logging purposes.
These streams provide a way for programs to interact with their environment in a standardized manner and their manipulation are essential for communication, error handling, and data processing in command-line programs and scripting.
Imagine you have a robot that can talk and listen. This robot has three special parts where it talks and listens from.
Mouth (Talk): This is where the robot talks or says things. It can say “Hello!” or “I like music!”
Ears (Listen): This is where the robot listens or hears things from. If you tell the robot something, it uses its ears to understand what you said.
Emergency Alarm (Oops): Sometimes, the robot might have a problem and need to tell you “Oops, something went wrong!” This is like a special alarm sound it makes.
These three parts are like the robot’s standard streams. The mouth is for talking (like standard output), the ears are for listening (like standard input), and the emergency alarm is for mistakes or problems (like standard error). Just like the robot can talk and listen to you, computer programs use these streams to talk to you, listen to you, and tell you if something went wrong.