[SOLVED] How do I write a loop in a gdb script?

How do I write a loop in a gdb script?

After adapting this answer, I wrote the following loop to simply print an array in gdb in a script called "gdb_script.gs". What am I doing wrong?

set $end=64  
while ($i<$end)
   print $i
   print volfrac($i, :, 1)
   set $i=$i+1
end

where volfrac(:,:,:) is a fortran array. I am getting the error:

 gdb_script.gs:14: Error in sourced command file:
 A syntax error in expression, near `<$end)'.

Solution

The other answer totally missed the point. The hint was the reported error:

    gdb_script.gs:14: Error in sourced command file:
    A syntax error in expression, near `<$end)'.

The hint is <$end), which means there is a syntax error in the while statement. By experimenting further, I am posting my results if others need it in the future:

 set $ipx=0
 set $end=32

 while ($ipx .lt. 32)
     print $ipx
     print ro($ipx, 1)
     set $ipx=$ipx+1
 end

The key was to use the fortran syntax for comparison ($ipx .lt. 32) instead of the usual "c" syntax ($ipx < 32).