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To demonstrate the value of the escape sequence feature, to output the text Foo on one line and Bar on the next line, the code must output a newline between the two words. The following code achieves the goal via text formatting and a hard-coded ASCII character value for newline (0x0A). This behaves as desired with the words on sequential lines ...
If the terminating character is a letter, the letter is the keycode value, and the optional number is the modifier value. The modifier value defaults to 1, and after subtracting 1 is a bitmap of modifier keys being pressed: Meta+Ctrl+Alt+⇧ Shift. So, for example, <esc>[4;2~ is ⇧ Shift+End, <esc>[20~ is function key F9, <esc>[5C is Ctrl+→.
For example, an ASCII (or extended ASCII) scheme will use a single byte of computer memory, while a UTF-8 scheme will use one or more bytes, depending on the particular character being encoded. Alternative ways to encode character values include specifying an integer value for a code point, such as an ASCII code value or a Unicode code point.
The NULL character (code 0) is represented by Ctrl-@, "@" being the code immediately before "A" in the ASCII character set. For convenience, some terminals accept Ctrl-Space as an alias for Ctrl-@. In either case, this produces one of the 32 ASCII control codes between 0 and 31.
The control code ranges 0x00–0x1F ("C0") and 0x7F originate from the 1967 edition of US-ASCII.The standard ISO/IEC 2022 (ECMA-35) defines extension methods for ASCII, including a secondary "C1" range of 8-bit control codes from 0x80 to 0x9F, equivalent to 7-bit sequences of ESC with the bytes 0x40 through 0x5F.
The ASCII "escape" character (octal: \033, hexadecimal: \x1B, or, in decimal, 27, also represented by the sequences ^[or \e) is used in many output devices to start a series of characters called a control sequence or escape sequence. Typically, the escape character was sent first in such a sequence to alert the device that the following ...
ASCII codes represent text in computers, telecommunications equipment, and other devices. ASCII has just 128 code points, of which only 95 are printable characters, which severely limit its scope. The set of available punctuation had significant impact on the syntax of computer languages and text markup.
In 1973, ECMA-35 and ISO 2022 [18] attempted to define a method so an 8-bit "extended ASCII" code could be converted to a corresponding 7-bit code, and vice versa. [19] In a 7-bit environment, the Shift Out would change the meaning of the 96 bytes 0x20 through 0x7F [a] [21] (i.e. all but the C0 control codes), to be the characters that an 8-bit environment would print if it used the same code ...