The syntax depends on the version of ArcGIS.
In the examples below, "Stack1" represents the name of the output grid stack. "[Grid1]", "[Grid2]", and "[Grid3]" represent the input grids to be stacked.
In ArcGIS 8.1.2 (Build 671), the MAKESTACK command syntax is:
MAKESTACK Stack1 [Grid1] [Grid2] [Grid3]
In ArcGIS 8.2 (Build 700), a keyword "LIST" must be used, similar to Workstation. The keyword "FILE" is not supported in the Raster Calculator.
MAKESTACK Stack1 LIST [Grid1] [Grid2] [Grid3]
MAKESTACK is not supported in the Raster Calculator of ArcGIS 8.1 (Build 642) or ArcGIS 8.1.1 (Build 649). If MAKESTACK is necessary, it must be run at the Grid: prompt in ArcInfo Workstation. An ArcInfo license is required for this operation.