In Programming in Scala, it gives a description on how to run Scala scripts from batch files (link).
For Windows
::#! @echo off call scala %0 %* goto :eof ::!# I'm having a problem googling ::#!. What does this mean? I know :: denotes a comment and in Unix #! is a direction to the shell to be used, but what is it exactly here? And the ::!#?
What exactly does %0 %* mean, and is it necessary to express it like this?
Is it possible to run multiple scripts from the same batch file?
This is a gimmick, but it works. It intends to replicate Unix shell's ability to invoke a particular command to process a shell file. So, here's the explanation:
::#! Lines starting with :: are comments in Windows shell, so this is just a comment.
@echo off Don't show lines executed from here on. The @ at the beginning ensure this line itself won't be shown.
call scala %0 %* Transfer execution to the scala script. The %0 means the name of this file itself (so that scala can find it), and %* are the parameters that were passed in its execution.
For example, say these lines are in a file called count.bat, and you invoked it by typing count 1 2 3. In this case, that line will execute scala count 1 2 3 -- in which case you'll get an error. You must invoke it by typing count.bat.
goto :eof Finish executing the script.
::!# Another comment line.
So, here's the trick... Scala, once invoked, will find the file passed as the first argument, check if the first line is ::#!, ignore everything up to the line ::!# if so, and then execute the rest of the file (the lines after ::!#) as a Scala script.
In other words, it is not the Windows shell that is smart, it's Scala. :-)
%0 indicates for the program name(the script file name maybe), %* indicates for the command line parameters list. %1 means the first parameter...
