The shell has always been there - from the dawn of Unix, it was the program that was run after you entered your login name and password on the terminal, to access the central computer. This device was also called teletypewriter, teletyper, or tty for short and the tty stuck from the early 70s, and the interface for a such a device, or terminal emulator is still called a tty, and in many programming languages outputting text for display in a terminal window still is called 'printing' originally it was not a metaphor but a fact. An example of a hard-copy terminal, a TeleType Model 33 ASR: One can imagine that a video terminal was a big improvement over such devices. To the programs, each window in your terminal emulator behaves like one of these devices most command line programs couldn't notice a difference (though you could find it difficult to connect a genuine VT100 to your MBP).Ī video terminal was the successor of a device called a hard-copy terminal, a device that would have a keyboard and printer - all the output from programs would be printed on the paper instead. most of the programs run in a window of the Terminal application look exactly the same as they would look if run on the big computer of 70s and the data displayed on such a terminal device. The Terminal program in OS X is a terminal emulator most of the terminal emulators of the present day still emulate that very same VT100 device quite closely, i.e.

As the personal computer came along, and graphical user interfaces became commonplace, there was (and still is) a way to access the Unix command line as if by such a terminal device - applications called terminal emulator. Thus decades ago a Unix computer was accessed via a terminal, which was a physical device. There usually were several of these connected to a single computer. A VT100 is not a computer, but just a keyboard and a display.

The machine in this picture is a (video) terminal, more specifically a VT100 by Digital Equipment Corporation.ĭecades ago when computers were big, instead of having personal computers for each user, they could have had a terminal, a dummy device with display and keyboard, that is connected to a main computer via a cable.

Linux vs unix vs windows vs mac