Editing IBM PC keyboard (section)

===From Teletype keyboards===
*{{key press|[[Control key|Ctrl]]}} shifts the value of letters and numbers from the ASCII graphics range, down into the [[ASCII]] control characters.  For example, CTRL-S is XOFF (stops many programs as they print to screen) CTRL-Q is XON (resume printing stopped by CTRL-S).
*{{key press|[[Escape key|Esc]]}} produces an ASCII [[escape character]]. It may be used to exit menus or modes.
*{{key press|~}} is the [[tilde]], an accent backspaced and printed over other letters for non-English languages. Nowadays the key does not produce a backspaceable character in US/UK keyboard layouts, and is used for 'not' or 'circa'.
*{{key press|`}} is a [[backtick]] or grave accent, also formerly backspaced over letters to write non-English languages; on some systems it is used as an opening quote.  The single quote ' is normally used for an acute accent.
*{{key press|^}} is a [[circumflex]], another accent for non-English languages. Also used to indicate [[exponentiation]] where [[superscript]] is not available.
*{{key press|*}} is an [[asterisk]], used to indicate a note, or multiplication.
*{{key press|_}} is an [[underscore]], which can be backspaced and overprinted to add emphasis, or in certain [[Programming Languages]] in place of a {{key press|[[Space key|Space]]}} to form a compound word where the use of {{key press|[[Space key|Space]]}} would yield several separate words.
*{{key press|{{!}}}} is a [[vertical bar]], originally used as a typographic separator for optical character recognition.  Many character sets break it in the middle so it cannot be confused with the numeral "1" or the letter "l" (in most [[EBCDIC]] [[codepage]]s, vertical bar and divided vertical bar are separate characters). This character is often known as a "pipe" (after its use in [[Unix shell]]s) or a "fencepost".