In computing and telecommunication, an escape character is a single character which in a sequence of characters signifies that what is to follow takes an alternative interpretation. Computing is usually defined like the activity of using and developing Computer technology Computer hardware and software. The term escape sequence refers to the escape character and the subsequent character or characters so modified. This article refers to codes used as commands for computing devices

Examples

Bourne shell

In sh, the * character is a wildcard character, expanding via globbing. The Bourne shell, or sh, was the default Unix shell of Unix Version 7, and replaced the Thompson shell, whose executable file had the same For other meanings of 'wild card' see Wild card. The term wildcard character has the following meanings Telecommunication In In Computer programming, the verb glob or globbing is used to refer to an instance of Pattern matching behavior In isolation, it expands to the names of all files in the working directory. In Computing, the working directory of a process is a directory of a hierarchical File system, if any dynamically associated with each process So to refer to a file literally called * you need to tell the shell to not interpret it in this way, which you do by preceding it with a backslash (\) -- this escapes the * character. Compare:

rm *# delete all files in the current directory

rm \*# delete the file named *

Programming languages

Many modern programming languages specify the doublequote character (") as a delimiter for a string literal. A programming language is an Artificial language that can be used to write programs which control the behavior of a machine particularly a Computer. A delimiter is a sequence of one or more characters used to specify the boundary between separate independent regions in Plain text or other data stream A string literal is the representation of a string value within the Source code of a Computer program. The backslash escape character provides one way to include doublequotes inside a string literal. For example, in Perl:

print "Nancy said "Hello World!" to the crowd. NOTES FOR EDITORS "Perl" is not an acronym (read the "Name" section below ";

produces a syntax error, whereas:

print "Nancy said \"Hello World!\" to the crowd. ";

produces the intended output.

Some programming languages also provide other ways to prevent this type of error, without requiring an escape character (see e. g. delimiter collision). A delimiter is a sequence of one or more characters used to specify the boundary between separate independent regions in Plain text or other data stream

Categories

• In alphabet coding schemes, a specially designated character, the occurrence of which in the data signifies that one or more of the characters to follow are from a different character code, i. An alphabet is a standardized set of letters basic written symbols each of which roughly represents a Phoneme, a Spoken language, either For other uses see Character. In Computer and machine-based Telecommunications terminology a character is a unit of Debt AIDS Trade in Africa (or DATA) is a Multinational non-government organization founded in January 2002 in London by U2 's In Communications a code is a rule for converting a piece of Information (for example a letter, Word, Phrase, or e. , have meanings other than normal.
• In a text-control sequence of characters, a control character that indicates the beginning of the sequence and the end of any preceding text. In Mathematics, a sequence is an ordered list of objects (or events In Computing and Telecommunication, a control character or non-printing character is a Code point (a Number) in a This is for instance used to control text terminals and printers (see escape sequence). A computer terminal is an electronic or electromechanical hardware device that is used for entering data into and displaying data from a Computer or a Computing This article refers to codes used as commands for computing devices
• In the ASCII character code, the character ESC with decimal code 27 and hexadecimal code 1B. American Standard Code for Information Interchange ( ASCII) The decimal ( base ten or occasionally denary) Numeral system has ten as its base. In Mathematics and Computer science, hexadecimal (also base -, hexa, or hex) is a Numeral system with a

Early reference to this term is found in Bob Bemer's IBM technical publications. Robert William Bemer ( February 8, 1920 &ndash June 22, 2004) was a computer scientist best known for his work at IBM during the late

The Escape key is usually found on standard PC keyboards. The Esc key is a key labeled Esc or Escape that is used to generate the ASCII Escape character ( Control - ASCII code However it is commonly absent from keyboards for PDAs and other devices not designed primarily for ASCII communications, and not generally used as part of the common user interface for applications on the Windows operating system. The DEC VT220 series was one of the few popular keyboards that did not have a dedicated Esc key, instead using one of the keys above the main keypad, though it is debatable if this contributed to the failure of the DEC personal computer series that used this keyboard.

External links

• That Powerful ESCAPE Character -- Key and Sequences - Bob Bemer
• Escape sequences and characters in Java, C, C++, VB, Python and other languages

See also

• Esc key
• Escape sequence
• ANSI escape code
• Delimiter
• Metacharacter
• Stropping