appending to a file

I first created a file:

>> fid=fopen('mongiss.lib', 'w')

fid =

     9

>> matrix=[1:3; 4:6]

matrix =

     1     2     3
     4     5     6

>> fprintf(fid, '%d %d\n',matrix)

ans =

    12

>> fclose(fid)

ans =

     0

>> load mongiss.lib

>> mongiss.lib

??? Attempt to reference field of non-structure array.

>> mongiss

mongiss =

     1     4
     2     5
     3     6

Then I tried to open it for appending without sucsess:

>> fid=fopen('mongiss.lib'. 'a')

??? fid=fopen('mongiss.lib'. 'a') | Error: Unexpected MATLAB operator.

What is wrong?

Answer 1

[TAB]

fid=fopen('mongiss.lib','a')