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VT100 terminals
. . . and later video display
terminals such as the DEC
VT100, all providing 80
characters-per-line fixed-width
ASCII output. Their
communications protocol is
still used today in graphical
windowing environments via
“terminal emulators” (e.g.,
xterm, konsole).
Photo: http://www.catb.org/esr/writings/taouu/html/
The VT100 was the first video terminal with microprocessor, and the first
to implement the ANSI X3.64 (= ECMA-48) control functions. For
instance, “ESC[7m” activates inverse mode and “ESC[0m” returns to
normal, where ESC is the ASCII “escape” control character (27 = 0x1B).
http://www.vt100.net/
http://www.ecma-international.org/publications/standards/Ecma-048.htm
man console_codes
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Unix tools design philosophy
I
Compact and concise input syntax, making full use of ASCII
repertoire to minimise keystrokes
I
Output format should be simple and easily usable as input for other
programs
I
Programs can be joined together in “pipes” and “scripts” to solve
more complex problems
I
Each tool originally performed a simple single function
I
Prefer reusing existing tools with minor extension to rewriting a new
tool from scratch
I
The main user-interface software (“shell”) is a normal replaceable
program without special privileges
I
Support for automating routine tasks
Brian W. Kernighan, Rob Pike: The Unix Programming Environment. Prentice-Hall, 1984.
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