Tilde
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The til die (~) is a grapheme with several uses. The name of the character comes from Spanish, from the Latin titulus meaning a title or superscription, and is pronounced ['tɪɫ.də], in English, or ['til.de], in Spanish. (In Spanish, however, "tilde" refers to an accent mark, as in "á" — the "~" is considered simply part of the letter ñ, like the dot in the letter i.) It was originally written over a letter as a mark of abbreviation (see below), but has since acquired a number of other uses as a diacritic mark or a character in its own right. In the latter capacity (especially in lexicography) it is also sometimes known as the swung dash (usually lengthened to ⁓).
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[edit] Diacritical use
In languages, the tilde is a diacritical mark (~) placed over a letter to indicate a change in pronunciation, such as nasalization.
It was first used in the polytonic orthography of Ancient Greek, as a variant of the circumflex accent, representing a rise in pitch followed by a return to standard pitch.
Later, it was used to make abbreviations in medieval Latin documents. When an "n" or "m" followed a vowel, it was often omitted, and a tilde (i.e. a small "n") was placed over the preceding vowel to indicate the missing letter. This is the origin of the use of tilde to indicate nasalization. The practice of using the tilde over a vowel to indicate omission of an "n" or "m" continued in printed books in French as a means of reducing text length until the 17th century. The tilde was also used occasionally to make other abbreviations, such as over the letter "q" to signify the word que (Fr. "that").
- Languages where the tilde is part of the symbol "ñ", for the palatal nasal consonant /ɲ/ include:
- Basque
- Galician
- Guarani
- Mapudungun
- Spanish. The tilded "n" ("ñ") developed from the grapheme "nn". It is usually regarded as a separate letter called eñe, rather than a letter-diacritic combination. The word tilde often designates any accent mark; for example, the acute accent in José is also called a tilde in Spanish.
- Tetum
- Languages and alphabets where the tilde is used as a sign of nasalization include:
- In the International Phonetic Alphabet (IPA). For example, [ljɔ̃] is the transcription of the pronunciation of the word "Lyon" in French.
- Portuguese. The tilde originated as a small "n" written above another letter, marking a Latin letter which had been elided. It indicates nasalization of the base vowel: "ã", "õ".
- Several native languages of South America, such as Guarani and Nheengatu.
- Languages and alphabets that use the tilde for other purposes:
- Estonian. The symbol "õ" stands for the close-mid back unrounded vowel, and it is considered an independent letter.
- Guarani. The tilded "G̃" ((Note that G/g with tilde is not available as a precomposed glyph in Unicode).) stands for the velar nasal consonant.
- In the International Phonetic Alphabet (IPA), the tilde is used through a symbol to mark velarization. For instance, [kʊ:ɫ] is the Australian English pronunciation of "cool", with the "dark l".
- Vietnamese. A tilde over a vowel represents a dipping tone (ngã).
[edit] Lexicography
In dictionaries, both bilingual and monolingual, tilde is usually referred to as swung dash. It is often used to replace the headword of an entry when it occurs within the entry, in order to save space. For example, ~ing would represent singing at the entry for sing.
[edit] Logic
In logic, it represents the negation of a proposition: thus ~p means "not p."
[edit] Electronics
It can approximate the sine wave symbol (∿, U+223F), which is used in electronics to indicate alternating current, in place of +, −, or ⎓ for direct current.
[edit] Punctuation
It is sometimes used as punctuation (instead of a hyphen or dash) between two numbers, to indicate that they are a range, rather than subtraction, or a hyphenated number (such as a part number or model number.) Japanese and other East Asian languages almost always use this convention, but it is often done for clarity in other languages as well. For example: 12~15 means "12 to 15", ~3 means "up to three" and 100~ means "100 and greater." In Japanese, the tilde is also used to separate a title and a subtitle in the same line. However in English, a tilde preceding a number sometimes represents an approximation (see below).
[edit] Mathematics
In mathematics, the tilde, sometimes pronounced "twiddle," is often used to denote an equivalence relation between two objects. Thus "x ~ y" means "x is equivalent to y" (Note that this is quite different from stating that x equals y.) Especially, it can be used to denote the asymptotical equality of two functions. For example, f(x) ~ g(x), means that limx→∞ f(x)/g(x) = 1.
In English it is sometimes used to represent approximation, for example ~10 would mean "approximately 10." Similar symbols are used in mathematics, such as in π ≈ 3.14, "π is about equal to 3.14." Since the double-tilde (≈) is not available from the keyboard except on the Macintosh (where it is Option-x on English layouts), the tilde (~) became a substitute for use in typed entry. There is also a triple-tilde (≋), which is used to show congruence.
In mathematical logic, ~ is used to represent negation. ~p means "not p." See the logic section above.
In statistics and probability theory, ~ means "is distributed as." See random variable.
Tilde placed below a letter in mathematics can represent a vector quantity.
Tilde is also used to indicate "approximately" (e.g. ~1) and "approximately equal to" (e.g. 1.902 ~= 2). The latter probably developed as a typed alternative to the libra symbol used for the same purpose in written mathematics, which is an equal sign (=) with the upper bar replaced by a bar with an upward hump or loop in the middle or, sometimes, a tilde. [Also see Approximation]. The symbol "≈" is also used for this purpose.
[edit] Computing
[edit] Directories and URLs
In Unix shells, the tilde indicates the current user's home directory (e.g., /home/username). When prepended to a particular username, it indicates that user's home directory (e.g., ~janedoe for the home directory of user janedoe, typically /home/janedoe). When some Unix shell commands overwrite a file, they can be made to keep a backup by renaming the original file as filename~.
Used in URLs on the World Wide Web, it often denotes a personal website on a Unix-based server. For example, http://www.example.com/~johndoe/ might be the personal web site of John Doe. This mimics the Unix shell usage of the tilde. However, when accessed from the web, file access is usually directed to a subdirectory in the user's home directory, such as /home/username/public_html or /home/username/www.
In URLs, the characters %7E (or %7e) may substitute a tilde if an input device lacks a tilde key. Thus, http://www.example.com/~johndoe/ and http://www.example.com/%7Ejohndoe/ are essentially the same URL.
[edit] Computer languages
It is used in the Perl programming language as part of the pattern match operators for regular expressions:
$a =~ /regex/returns true if the variable is matched.$a !~ /regex/returns false if the variable is matched.
The popularity of Perl's regular expression and syntax has led to the use of these operators in other programming languages, such as Ruby.
In the C and C++ programming languages, the tilde character is used to invert all bits of an integer, following the notation in logic. In C++, the tilde is also used as the first character in a class's method name (where the rest of the name must be the same name as the class) to indicate a destructor - a special method which is called at the end of the object's life.
In the D programming language, the tilde is used as an array concatenation operator, as well as to indicate an object destructor.
In the CSS stylesheet language, the tilde is used for the indirect adjacent combinator as part of a selector.
In the Inform programming language, the tilde is used to indicate a quotation mark inside a quoted string.
In "text mode" of the LaTeX typesetting language a stand-alone tilde can be obtained with \~{} and for use as a diacritics, e.g., like \~{n} rendering "ñ". In "math mode" a stand-alone tilde can be written as \tilde{~} and as diacritics, e.g., \tilde{x}. For a wider tilde the \widetilde can be used. The \sim command produce a tilde-like character that is often used in probability mathematical equations, and the double-tilde is obtained with \approx. In both text and math mode a tilde on its own (~) is rendering a white space with no line breaking.
The Emacs text editor forms the names used for backup files by appending a tilde to the original file name.
[edit] Microsoft filenames
The tilde was part of Microsoft's filename mangling scheme when it developed the VFAT filesystem. This upgrade introduced long filenames to Microsoft Windows, and permitted additional characters (such as the space) to be part of filenames, which were prohibited in previous versions. Programs written prior to this development could only access filenames in the so-called 8.3 format—the filenames consisted of a maximum of eight alphanumeric characters, followed by a period, followed by three more alphanumeric characters. In order to permit these legacy programs to access files in the VFAT filesystem, each file had to be given two names—one long, more descriptive one, and one that conformed to the 8.3 format. This was accomplished with a name-mangling scheme in which the first six characters of the filename are followed by a tilde and a digit. For example, "Program Files" becomes "PROGRA~1".
[edit] Other uses
In most online computer games, tilde (located below the Escape key on US keyboards, a key is nevertheless in the same location on other layouts that serves the same function) can be used to bring down the console. This will allow cheating, seeing previous scores, or chat logs.
Computer programmers use the tilde in various ways and often call the symbol (as opposed to the diacritic) a squiggle or a twiddle. According to the Jargon File, other synonyms sometimes used in programming include not, approx, wiggle, enyay (after eñe) and (humorously) sqiggle.
See History of the tilde for a history of how the tilde came to become part of the standard computer character sets.
In Google search, the tilde entered before a search query word displays listings with that word and synonyms of it. [1]
To type a tilde on a Spanish keyboard, you can use AltGr+4. On the Macintosh keyboard, Option-n followed by another letter places the tilde over that letter.
On Wikipedia, four tildes (~~~~) produce a signature when the article is saved.
[edit] Juggling notation
In the juggling notation system beatmap, tilde can be added to either "hand" in a pair of fields to say "cross the arms with this hand on top". Mills Mess is thus represented as (~2x,1)(1,2x)(2x,~1)* [2].
[edit] Vertical tilde
Unicode has a combining vertical tilde character, at U+033E ̾. It is used to indicate middle tone in the Lithuanian language[1] and for transliteration of the Cyrillic palatalization sign (U+484 ҄)[citation needed].
[edit] Popular culture
- On the TV Network TechTV, there were certain shows with two virtual characters, "Tilde" and "Dash".
- On certain Counter-Strike Internet Forums, the slogan "Keep away from that tilde" is used, referring to that in most First Person Shooter games, by default the tilde key on the keyboard opens up the console, which may allow cheating.
- In the post-cyberpunk novel ~ (ISBN 1-4196-1092-9) by Ray Ogar, the author uses numerous allusions to the various computer uses of the ~. One such reference in the novel suggests that clones are copies of humans with truncated information, dependent on multiple versions, and refer to approximations of some human exemplar.
- When used in conversations via email or instant messenger it can be seen as a sarcasm mark or, in Asian cultures, as a extension of the final syllable to produce the same effect as "whyyyyyy" with "why~~"
[edit] See also
[edit] References
- ^ Lithuanian Standards Board (LST), proposal for a zigazag diacritic.
[edit] External links
- History of the Tilde
- Diacritics Project All you need to design a font with correct accents
| The ISO basic Latin alphabet | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Aa | Bb | Cc | Dd | Ee | Ff | Gg | Hh | Ii | Jj | Kk | Ll | Mm | Nn | Oo | Pp | Rr | Ss | Tt | Uu | Vv | Ww | Xx | Yy | Zz | |
| history • palaeography • derivations • diacritics • punctuation • numerals • Unicode • list of letters | |||||||||||||||||||||||||
