EXIST EXIST Test for Existence

Usage

Tests for the existence of a variable, function, directory or
file.  The general syntax for its use is

  y = exist(item,kind)

where item is a string containing the name of the item
to look for, and kind is a string indicating the type 
of the search.  The kind must be one of 
  -  'builtin' checks for built-in functions

  -  'dir' checks for directories

  -  'file' checks for files

  -  'var' checks for variables

  -  'all' checks all possibilities (same as leaving out kind)

You can also leave the kind specification out, in which case
the calling syntax is

  y = exist(item)

The return code is one of the following:
  -  0 - if item does not exist

  -  1 - if item is a variable in the workspace

  -  2 - if item is an M file on the search path, a full pathname
 to a file, or an ordinary file on your search path

  -  5 - if item is a built-in FreeMat function

  -  7 - if item is a directory

Note: previous to version 1.10, exist used a different notion
of existence for variables: a variable was said to exist if it 
was defined and non-empty.  This test is now performed by isset.
