<grammar> Strictly, a variable used in metasyntax, but often used for any name used in examples and understood to stand for whatever thing is under discussion, or any random member of a class of things under discussion. The word foo is the canonical example. To avoid confusion, hackers never (well, hardly ever) use "foo" or other words like it as permanent names for anything. In filenames, a common convention is that any filename beginning with a metasyntactic-variable name is a scratch file that may be deleted at any time. To some extent, the list of one's preferred metasyntactic variables is a cultural signature. They occur both in series (used for related groups of variables or objects) and as singletons. Here are a few common signatures: foo, bar, baz, quux, quuux, quuuux...: MIT/Stanford usage, now found everywhere. At MIT (but not at Stanford), baz dropped out of use for a while in the 1970s and '80s. A common recent mutation of this sequence inserts qux before quux. bazola, ztesch: Stanford (from mid-'70s on). foo, bar, thud, grunt: This series was popular at CMU. Other CMU-associated variables include ack, barf, foo, and gorp. foo, bar, fum: This series is reported to be common at Xerox PARC. fred, barney: See the entry for fred. These tend to be Britishisms. toto, titi, tata, tutu: Standard series of metasyntactic variables among francophones. corge, grault, flarp: Popular at Rutgers University and among GOSMACS hackers. zxc, spqr, wombat: Cambridge University (England). shme: Berkeley, GeoWorks, Ingres. Pronounced /shme/ with a short /e/. foo, bar, zot: Helsinki University of Technology, Finland. blarg, wibble: New Zealand Of all these, only "foo" and "bar" are universal (and baz nearly so). The compounds foobar and "foobaz" also enjoy very wide currency. Some jargon terms are also used as metasyntactic names; barf and mumble, for example. See also Commonwealth Hackish for discussion of numerous metasyntactic variables found in Great Britain and the Commonwealth. [Jargon File] (1995-11-13)

A metasyntactic variable is a specific word or set of words identified as a placeholder in computer science and specifically computer programming. These words are commonly found in source code and are intended to be modified or substituted before real-world usage.

/kwuhks/ [Mythically, from the Latin semi-deponent verb quuxo, quuxare, quuxandum iri; noun form variously "quux" (plural "quuces", anglicised to "quuxes") and "quuxu" (genitive plural is "quuxuum", for four u-letters out of seven in all, using up all the "u" letters in Scrabble).] 1. Originally, a metasyntactic variable like foo and foobar. Invented by Guy Steele for precisely this purpose when he was young and naive and not yet interacting with the real computing community. Many people invent such words; this one seems simply to have been lucky enough to have spread a little. In an eloquent display of poetic justice, it has returned to the originator in the form of a nickname. 2. See foo; however, denotes very little disgust, and is uttered mostly for the sake of the sound of it. 3. Guy Steele in his persona as "The Great Quux", which is somewhat infamous for light verse and for the "Crunchly" cartoons. 4. In some circles, used as a punning opposite of "crux". "Ah, that's the quux of the matter!" implies that the point is *not* crucial (compare tip of the ice-cube). [Jargon File]

/grawlt/ Yet another metasyntactic variable, invented by Mike Gallaher and propagated by the GOSMACS documentation. See corge. [Jargon File]

/korj/ Yet another metasyntactic variable, named after a cat invented by Mike Gallaher and propagated by the GOSMACS documentation. See grault. [Jargon File] (1994-12-08)

/gar'plee/ A metasyntactic variable like foo, once popular among SAIL hackers. [Jargon File] (1994-11-03)

n.
Acronym of free-loading oxygen breather. Submarine slang for a non-crew passenger, unqualified crewmember or other useless person. A waste of life support.
Until you're qualified, you're nothing but a flob.

In computer programming, a variable is an abstract storage location paired with an associated symbolic name, which contains some known or unknown quantity of information referred to as a value; or in simpler terms, a variable is a named container for a particular set of bits or type of data (like integer, float, string etc...).

<programming, operating system> A variable that is bound in the current environment. When evaluating an expression in some environment, the evaluation of a variable consists of looking up its name in the environment and substituting its value. Most programming languages have some concept of an environment but in Unix shell scripts it has a specific meaning slightly different from other contexts. In shell scripts, environment variables are one kind of shell variable. They differ from local variables and command line arguments in that they are inheritted by a child process. Examples are the PATH variable that tells the shell the file system paths to search to find command executables and the TZ variable which contains the local time zone. The variable called "SHELL" specifies the type of shell being used. These variables are used by commands or shell scripts to discover things about the environment they are operating in. Environment variables can be changed or created by the user or a program. To see a list of environment variables type "setenv" at the csh or tcsh prompt or "set" at the sh, bash, jsh or ksh prompt. In other programming languages, e.g. functional programming languages, the environment is extended with new bindings when a function's parameters are bound to its {actual arguments} or when new variables are declared. In a block-structured procedural language, the environment usually consists of a linked list of activation records. (1999-01-26)

An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. They are part of the environment in which a process runs.