bajger / pharolauncher-cli Goto Github PK

I've often thought it was neat that VisualWorks has executable image files by virtue of the simple expedient of the first few bytes being a shell script:

00000000: 6578 6563 2076 6973 7561 6c20 2d3d 2430  exec visual -=$0
00000010: 2022 2440 220a 0a00 0000 0000 0000 0000   "$@"........... 

which obviously just finds their vm visual on the PATH and supplies the image as the first argument, passing along any other arguments that were specified. On Windows, the filetype .im is associated with visual.exe but, whichever architecture it runs on, their vm just ignores the first N bytes of the image file which makes it possible to use them for a script in this manner.

What if we had a fully fledged launcher image which was like this:

|#!/bin/bash script -->|M|<-- headless launcher image -->|<----- main image ----------------------->| 

and a VM that, if it was given an image starting with a shebang, always loaded the object image after the marker, |M|.

Then the bash script could do simple things like letting you know you don't have a VM on the path, and offer to download the correct one to run the headless launcher/maintenance image and once that's running we can use that to do all the good command line stuff you have listed in your proposal, including launching one or more instances of the main image and (as with the current graphical launcher) optionally quitting having done so.