Editing Vertical bar (section)

====Disjunction====
In many programming languages, the vertical bar is used to designate the [[Logical disjunction|logic operation ''or'']], either [[Bitwise operation|bitwise]] ''or'' or [[Boolean data type|logical]] ''or''.

Specifically, in [[C (programming language)|C]] and other languages following [[C syntax]] conventions, such as [[C++]], [[Perl]], [[Java (programming language)|Java]] and [[C Sharp (programming language)|C#]], <code>a | b</code> denotes a [[Bitwise operation#OR|bitwise ''or'']]; whereas a double vertical bar <code>a || b</code> denotes a ([[Minimal evaluation|short-circuited]]) [[logical disjunction|logical ''or'']]. Since the character was originally not available in all [[code page]]s and keyboard layouts, [[ANSI C]] can transcribe it in form of the [[C trigraph|trigraph]] <code>??!</code>, which, outside string literals, is equivalent to the <code>|</code> character.

In [[regular expression]] syntax, the vertical bar again indicates logical ''or'' ([[alternation (formal language theory)|alternation]]). For example: the Unix command <code>[[grep]] -E 'fu|bar'</code> matches lines containing 'fu' or 'bar'.