For questions relating to the backtick character (`), also known as the backquote, which has various special meanings in computing.
A backtick or backquote or grave accent is the character,
`
On British and American QWERTY keyboards, this is located in the upper left corner, next to the 1 key. It is notoriously difficult to type on some European keyboards, requiring up to four keystrokes.
Backticks were introduced by Unix shells to run a sub-shell. The concept has been adopted by other languages and tools such Perl, PHP, Ruby, and Make. The newer alternative syntax $(<command>) in POSIX-compliant shells is more flexible as it allows nesting.
In Python 2, backticks enclose an expression to be evaluated and converted to its string representation. This feature was removed in Python 3, as it was deemed not sufficiently beneficial to warrant the syntax. The same effect can be accomplished with repr() instead.
In Markdown, backticks are used as a shorthand for emitting <code></code> tags in HTML.
In TeX typesetting, a backtick renders as an opening curly quote (‘).
In the programming languages D and Go, backticks surround string literals.
Further uses of backticks in computing can be found in the Wikipedia article on the grave accent.
