To decompile a compiled help file from the command line
From a command prompt or from the Run command, type:
-decompile folder chm
where -decompile is the switch, folder is the name of the destination folder where you want the decompiled files to be copied, and chm is the name of the compiled help (.chm) file you want to decompile.
Client-side command line switches are part of the HTML Help executable program (Hh.exe) and therefore work when HTML Help Workshop is not set up.