# `bexists` - Command Reference

> Check which builtins exist

## Description

`bexists` takes an array of parameters and returns which commands have been
compiled into Murex. The 'b' in `bexists` stands for 'builtins'

## Usage

    bexists command... -> <stdout>

## Examples

    » bexists: qr gzip runtime config
    {
        "Installed": [
            "runtime",
            "config"
        ],
        "Missing": [
            "qr",
            "gzip"
        ]
    }

## Detail

This builtin dates back to the start of Murex when all of the builtins were
considered optional. This was intended to be a way for scripts to determine
which builtins were compiled. Since then `runtime` has absorbed and centralized
a number of similar commands which have since been deprecated. The same fate
might also happen to `bexists` however it is in use by a few modules and for
that reason alone it has been spared from the axe.

## See Also

* [Modules and Packages](../user-guide/modules.md):
  An introduction to Murex modules and packages
* [`fexec` ](../commands/fexec.md):
  Execute a command or function, bypassing the usual order of precedence.
* [`runtime`](../commands/runtime.md):
  Returns runtime information on the internal state of Murex