How can I install estoolkit?

On Mac, use AppleScript. Paste the following into a new Script Editor document (/Applications/Utilities/Script Editor.app) and save as `aitool.applescript`:

#!/usr/bin/env osascript

property _name : "aitool"

on run argv
	if argv is {} then set argv to {"-h"}
	set opt to item 1 of argv
	set argv to rest of argv
	
	if {opt} is in {"-h", "--help"} then
		log "Usage:"
		log _name & " -h"
		log _name & " -o /path/to/file.ai [ file ... ]"
		log _name & " -r /path/to/file.jsx [ argument ... ]"
		
	else if {opt} is in {"-o", "--open"} then
		repeat with pth in argv
			set f to POSIX file pth
			try
				tell application "Adobe Illustrator" to open f without dialogs
			on error msg number num
				log msg & " (" & num & ")"
			end try
		end repeat
		
	else if {opt} is in {"-r", "--run"} then
		set pth to item 1 of argv
		set argv to rest of argv
		set f to POSIX file pth
		try
			tell application "Adobe Illustrator"
				do javascript f with arguments argv
			end tell
		on error msg number num
			log msg & " (" & num & ")"
		end try
		
	else
		log "Unknown option: " & opt
	end if
	
end run

In Terminal.app, make it executable and move it to a directory that on your shell $PATH:

chmod +x aitool.applescript
sudo mv aitool.applescript /usr/local/bin/aitool

You can now run from Terminal, e.g.

aitool -r /Users/foo/myscript.jsx

Support for relative file paths, more robust error handling (e.g. file not found), etc is left as an exercise. (This may help.)

This works on Mac... The `-a` flag tells the open command which program to open the file with.

open -a Adobe\ Illustrator ~/path/to/script.js

I don't know the answer, but I think people will want to know what platform—MacOS or Windows?