function command( repl ) {
	return onCommand;

	/**
	* Reloads a previously loaded module.
	*
	* @private
	* @param {string} id - module id or path
	* @returns {*} resolved module
	*/
	function onCommand( id ) {
		var err;
		if ( !isString( id ) ) {
			err = new TypeError( format( 'invalid argument. Must provide a string. Value: `%s`.', id ) );
			debug( 'Error: %s', err.message );
			repl._ostream.write( 'Error: '+err.message+'\n' );
			return;
		}
		// Resolve the module id to a path:
		id = repl._context.require.resolve( id );

		// Remove the module from the `require` cache:
		debug( 'Removing module from require cache: %s', id );
		delete repl._context.require.cache[ id ];

		// Re-require the module:
		debug( 'Re-requiring module: %s', id );
		return repl._context.require( id );
	}
}
Returns a callback to be invoked upon calling the `rerequire` command.

@private
@param {REPL} repl - REPL instance
@returns {Function} callback