| FreeMat
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Section: Inspection Functions
The syntax for iscellstr is 
x = iscellstr(y)
and it returns a logical 1 if the argument is a cell array in which every cell is a character array (or is empty), and a logical 0 otherwise.
Here is a simple example
--> A = {'Hello','Yellow';'Mellow','Othello'}
A = 
 [Hello] [Yellow] 
 [Mellow] [Othello] 
--> iscellstr(A)
ans = 
 1