# exists()

## Purpose

exists($!path!varname)

This function checks if the specified variable exists, in other words: contains a value. A variable that once was set and later on unset does also not exist.

The function accepts a single argument, which needs to be a variable. It returns 0 if the variable does not exist and 1 otherwise. The function can be combined with any other expression to form more complex expressions.

Added in version 8.2010.10.

## Example

    if exists(!$path!varname) then ...
    if not exists($.local!var) then ...
    if exists($!triggervar) and $msg contains "something" then ...

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