Control-\

Summary

In computing, control-\ is a control character in ASCII code and the Basic Latin code block of Unicode, also known as the file separator or field separator (FS) character. It is generated by pressing the \ key while holding down the Ctrl key on a computer keyboard, and has the decimal value 28 (or 1c in hexadecimal). It is the highest-level of the four separators in the ASCII C0 and C1 control codes; the others are control-] (group separator), control-^ (record separator), and control-_ (unit separator).[1] It was one of eight codes reserved as separators in the 1963 version of the ASCII standard;[2] these were reduced to four separators in a 1965 revision of the standard.[3]

In its use as a file separator, this character can be used to subdivide textual data into records or other semantic units; for instance, it has this role in the ANSI/NIST-ITL Standard Data Format for the Interchange of Fingerprint, Facial & Other Biometric Information.[1]

Under most UNIX-based operating systems control-\ is used to terminate a running process from a command shell and have it produce a memory core dump by sending it a SIGQUIT signal.[4] Other similar ways of terminating or interrupting a shell process include Control-C, Control-Z, and the kill command.

As a character that can be easily typed on most keyboards, but with no standardized meaning, control-\ is often used as a keyboard shortcut in different graphical user interfaces, with various unrelated effects. For instance, some versions of Windows File Manager use it to de-select all selected files.[5] In Adobe InDesign, it has been used to mark a point in a line of text as the starting position of a hanging indent.[6]

References edit

  1. ^ a b Mangold, Kevin (August 22, 2016), "Annex B: Traditional Encoding", Data Format for the Interchange of Fingerprint, Facial & Other Biometric Information ANSI/NIST-ITL 1-2011 NIST Special Publication 500-290 Edition 3, American National Standards Institute and National Institute of Standards and Technology, pp. 509–522, doi:10.6028/NIST.SP.500-290e3
  2. ^ Gorn, S.; Bemer, R. W.; Green, J. (August 1963), "American standard code for information interchange", Communications of the ACM, 6 (8): 422–426, doi:10.1145/366707.367524
  3. ^ Mackenzie, Charles E. (1980), "23.2 ASCII-1965", Coded Character Sets, History and Development (PDF), The Systems Programming Series, Addison-Wesley Publishing Company, Inc., pp. 423–425, ISBN 978-0-201-14460-4
  4. ^ Stevens, W. Richard; Rago, Stephen A. (2013), Advanced Programming in the UNIX Environment, Addison-Wesley professional computing series, Pearson Education, p. 300, ISBN 9780321637734
  5. ^ Livingston, Brian (October 19, 1992), "More on file managing, networking, and mouse customization", Window Manager, InfoWorld, p. 22
  6. ^ Cohen, Sandee (2008), InDesign CS4 for Macintosh and Windows: Visual QuickStart Guide, Peachpit Press, p. 161, ISBN 9780321648853