The underscore , even deep line is that in ASCII - character set on position 95 ( decimal ) and 0x5F ( hexadecimal included) character ( "_"). Its meaning varies depending on the context and area of application.
Position on keyboards
On the German standard keyboard (" QWERTZ "; commonly used in Germany and Austria ) as well as on the Swiss keyboard , the underscore is located immediately to the left of the right shift key ( ⇧) and is activated together with it (if you do not press the shift key, you get a hyphen ) . The -key on the numeric keypad cannot create an underscore.
On keyboards with a British or American layout (" QWERTY ") the actuation and assignment of the key is identical, but the key itself is located in the top row of the letter block to the right of the key 0(zero).
On the French keyboard (" AZERTY ") the character is located together with the one 8above the keys Uand Iand is generated without pressing the shift key ( ⇧).
The underscore was used in its original function on typewriters : a word was underlined by moving the slide or carriage (depending on the technology, the type wheel or the ball head ) back to the first word to be underlined and then typing in the appropriate number of underlines. For a long time, this was the only way to label directly with the machine in addition to blocking .
electronic data processing
- With text-based screen systems ( e.g. VT100 systems, host systems , ncurses ), the underscore is used to symbolize input fields. With the introduction of graphical user interfaces , this meaning became less important.
- In older versions of word processing programs such as Word for DOS , the underscore was used to mark the font style in italics : a word enclosed in underscores was only shown in italics on the final printout. For reasons of compatibility , many word processing programs still provide this function today, but it can usually be deactivated. Example:
|Text input||Print output|
|Letter to Mr. _Müller_||Letter to Mr. Müller|
- In the local part ( directory structure and file names ) of URLs , the space is now correctly coded everywhere replaced (as hexadecimal equivalent :)
%20; for this reason, the meaning of the underscore as a replacement for the space has decreased. Often, however, the underscore is still used as a preventive measure.
- In Usenet and in other text-based media, such as IRC , the underscore is used to emphasize a word, since formatting is not possible here. Example: _Dir_ doesn't care at all!
- In IRC , the underscore is often placed after a nickname if the desired name has already been taken. If z. For example, if someone wants to log in to a server with the nick "Max", but this name is already taken, then he usually uses "Max_".
- Alternatively, a chain of underscores can be used to represent a dividing line or - as in the past - a space in which texts can be inserted on printouts. A tidy typeface can only be guaranteed if there are no spaces left or right of the underline. While this would be a mistake anyway, it is still the case with some fonts and printing techniques.
- In some cases the underscore serves as a so-called wildcard or joker character and represents a single omitted character (for example in SQL ).
- In addition, the underscore still serves as a replacement for a space where it is not allowed. These can be, for example, e-mail addresses, names of variables or file names . Please note, however, that the different positions of the underscore and the space in the ASCII table can change the sort order. Expressly as such surrogate underscore, for example, in the ISO 9660 specification for CD-ROM - file systems provided.
- In the computer-aided formula set, a subscript (such as an index) is represented by an underscore in some programs (e.g. x_a = ).
- On most keyboards, typographically , the underscore on the double-assigned key is shown in its half of the key on the middle line and not the base line and is actually shown as a dash . The dash is actually generated with the same key (at least on the Mac, AT) with alt + key, the underscore with shift (shift) + key.
The Hebrew alphabet uses the underscore as a vowel sign ( nikud ) .
From 2003 the underscore will be used in the context of gender-equitable language : teachers . Between the masculine and feminine word form, it should express “a place” for further genders and gender identities (compare Divers , Third Gender ). The spelling with underscores replaces the generic masculine ( teachers generalizing for all teachers) and shortens the term teachers . The gender gap was proposed as an alternative to the Binnen-I (teachers) and pushed back from 2010 through the use of the gender asterisk : teachers . In 2019 the variant with a gender colon came up: teachers .
- Macron : underscore as the undersign