Here I'm adding some more photos of license files. When I opened both license files for arcgis and erdas, they look like this. First image is ArcGIS license file which is very similar to what @U2ros described above except "son". I think I can change 27001 into 27005 etc.
The ERDAS Imagine course manual covers each of the 10 on-line modules as a Microsoft Word Document or Adobe PDF. The manual can be printed to serve as a useful companion when working within the ERDAS Imagine software, rather than switching between windows on your computer desktop.