Backspace ( ← Backspace ) is the keyboard key that in typewriters originally pushed the carriage one position backwards, and in modern computer systems typically moves the display cursor one position backwards, deletes the character at that position, and shifts back any text after that position by one character.
19-435: Although the term "backspace" is the traditional name of the key which steps the carriage back and/or deletes the previous character, typically to the left of the cursor, the actual key may be labeled in a variety of ways, for example delete , erase , or with a left pointing arrow. A dedicated symbol for "backspace" exists as U+232B ⌫ but its use as a keyboard label is not universal. Some very early typewriters labeled this key
38-543: A script property , specifying which writing system it is intended for, or whether it is intended for multiple writing systems. This, also, is independent of block. In descriptions of the Unicode system, a block may be subdivided into more specific subgroups, such as the " Chess symbols " in the Miscellaneous Symbols block (not to be confused with the separate Chess Symbols block). Those subgroups are not "blocks" in
57-400: A key that functions as a backspace key, and a key that functions as a delete key. Smaller Mac keyboards, such as laptop keyboards, have only a key that functions as a backspace key. In some typewriters, a typist would, for example, type a lowercase letter A with acute accent (á) by typing a lowercase letter A, backspace, and then the acute accent key. This technique (also known as overstrike )
76-617: A total of 36 variants. The following Unicode-related documents record the purpose and process of defining specific characters in the Miscellaneous Technical block: Unicode block A Unicode block is one of several contiguous ranges of numeric character codes ( code points ) of the Unicode character set that are defined by the Unicode Consortium for administrative and documentation purposes. Typically, proposals such as
95-509: Is commonly used to go back a page or up one level in graphical web or file browsers. Pressing the backspace key on a computer terminal would generate the ASCII code 08, BS or Backspace, a control code which would delete the preceding character. That control code could also be accessed by pressing ( Control + H , as H is the eighth letter of the Latin alphabet . Terminals which did not have
114-481: Is the basis for such spacing modifiers in computer character sets such as the ASCII caret (^, for the circumflex accent). Backspace composition no longer works with typical modern digital displays or typesetting systems. It has to some degree been replaced with the combining diacritical marks mechanism of Unicode , though such characters do not work well with many fonts, and precomposed characters continue to be used. Some software like TeX or Microsoft Windows use
133-488: The backspacer key. Backspace is distinct from the delete key , which in a teletypewriter would punch out all the holes in punched paper tape to strike out a character, and in modern computers deletes text at or following the cursor position. Also, the delete key often works as a generic command to remove an object (such as an image inside a document, or a file in a file manager ), while backspace usually does not. Full-size Mac keyboards have two keys labeled delete ;
152-578: The Berkeley Unix terminal line discipline . This shortcut has also made it into the insert mode of the Vi text editor and its clone Vim . ^U deletes a line. In a mainframe environment, to backspace means to move a magnetic tape backwards, typically to the previous block. Miscellaneous Technical#Block Miscellaneous Technical is a Unicode block ranging from U+2300 to U+23FF. It contains various common symbols which are related to and used in
171-446: The addition of new glyphs are discussed and evaluated by considering the relevant block or blocks as a whole. Each block is generally, but not always, meant to supply glyphs used by one or more specific languages, or in some general application area such as mathematics , surveying , decorative typesetting , social forums, etc. Unicode blocks are identified by unique names, which use only ASCII characters and are usually descriptive of
190-415: The backspace code mapped to the function of moving the cursor backwards and deleting the preceding character would display the symbols ^H ( caret , H) when the backspace key was pressed. Even if a terminal did interpret backspace by deleting the preceding character, the system receiving the text might not. Then, the sender's screen would show a message without the supposedly deleted text, while that text, and
209-444: The code point. ) The size of a block may range from the minimum of 16 to a maximum of 65,536 code points. Every assigned code point has a glyph property called "Block", whose value is a character string naming the unique block that owns that point. However, a block may also contain unassigned code points, usually reserved for future additions of characters that "logically" should belong to that block. Code points not belonging to any of
SECTION 10
#1733105348527228-419: The deletion codes, would be visible to the recipient. This sequence is still used humorously for epanorthosis by computer literates, denoting the deletion of a pretended blunder, much like a strikethrough ; in this case, however, the ^H symbol is faked by typing a regular '^' followed by typing a regular 'H'. Example: An alternative sometimes seen is ^W , which is the shortcut to delete the previous word in
247-514: The named blocks, e.g. in the unassigned planes 4–13, have the value block="No_Block". Simply belonging to a particular Unicode block does not guarantee the certain particular properties of the characters it is or will be expected to contain. The identity of any character is determined by its properties stated in the Unicode Character Database. For example, the contiguous range of 32 noncharacter code points U+FDD0..U+FDEF share none of
266-457: The nature of the symbols, in English ; such as "Tibetan" or "Supplemental Arrows-A". (When comparing block names, one is supposed to equate uppercase with lowercase letters, and ignore any whitespace, hyphens, and underbars; so the last name is equivalent to "supplemental_arrows__a" and "SUPPLEMENTALARROWSA". Blocks are pairwise disjoint ; that is, they do not overlap. The starting code point and
285-509: The opposite method for diacritical marks, namely positioning the accent first, and then the base letter on its position. In modern systems, the backspace key is often mapped to the delete character (0x7f in ASCII or Unicode), although the backspace key's function of deleting the character before the cursor remains. In computers, backspace can also delete a preceding newline character, something generally inapplicable to typewriters. The backspace key
304-487: The properties common to the other characters in the Arabic Presentation Forms-A block, that they are certainly not Arabic script characters or "right-to-left noncharacters", and are assigned there as a filler to this block given that it has been agreed that no further Arabic compatibility characters will be encoded. Each Unicode point also has a property called " General Category ", that attempts to describe
323-531: The role of the corresponding symbol in the languages or applications for whose sake it was included in the system. Examples of General Categories are "Lu" (meaning upper-case letter), "Nd" (decimal digit), "Pi" (open-quote punctuation), and "Mn" (non-spacing mark, i.e. a diacritic for the preceding glyph). This division is completely independent of code blocks: the code points with a given General Category generally span many blocks, and do not have to be consecutive, not even within each block. Each code point also has
342-489: The size (number of code points) of each block are always multiples of 16; therefore, in the hexadecimal notation, the starting (smallest) point is U+ xxx 0 and the ending (largest) point is U+ yyy F, where xxx and yyy are three or more hexadecimal digits. (These constraints are intended to simplify the display of glyphs in Unicode Consortium documents, as tables with 16 rows labeled with the last hexadecimal digit of
361-649: The various technical, programming language, and academic professions. For example: It also includes most of the uncommon symbols used by the APL programming language. In Unicode , Miscellaneous Technical symbols placed in the hexadecimal range 0x 2300 –0x 23FF , (decimal 8960–9215), as described below. The Miscellaneous Technical block contains eighteen emoji : U+231A–U+231B, U+2328, U+23CF, U+23E9–U+23F3 and U+23F8–U+23FA. All of these characters have standardized variants defined, to specify emoji-style (U+FE0F VS16) or text presentation (U+FE0E VS15) for each character, for
#526473