How do you access ARGV in Mathematica?

Question

I'd like to write command line scripts in Mathematica, but I can't seem to find an Argv[i_Integer] like function. (The docs are FANTASTIC otherwise.)

Mammon

similar question: If doing “math foo bar”, how to get foo and bar inside Mathematica? – Downtrodden

Answer 1

$CommandLine works for Mathematica, MathematicaScript, MathKernel, and math.

args.ma:

#!/usr/bin/env MathKernel -script

Print[$CommandLine]

Example:

$ ./args.ma a b c
{"MathKernel", "-script", "./args.ma", "a", "b", "c"}

Mammon

Answer 2

It seems that $ScriptCommandLine is the variable you would need for this, assuming you're using MathematicaScript for scripting. If you use math or MathKernel -script it would be $CommandLine.

Other relevant discussions: a rather old one and one in the MMA toolbag.

Arronarrondissement

Thanks. Unfortunately, MathKernel reports $ScriptCommandLine as empty {}, no matter the actual arguments supplied. And MathematicaScript reports Could not find Mathematica installation directory. – Mammon

@Mammon Are the executables on your path? – Arronarrondissement

@Mammon .... and did you see this line in the docs: "The first line of the script must contain the -script option, which must be the last option on the line." – Arronarrondissement

@Mammon "If no -script option was provided, $ScriptCommandLine gives an empty list." – Arronarrondissement

@Mammon This all still assuming you're using MathematicaScript. – Arronarrondissement

@Mammon What's the value of $InstallationDirectory when you run Mathematica from the frontend? – Palestrina

$InstallationDirectory = "/Applications/Mathematica.app", from both MathKernel -script and from the Mathematica GUI. – Mammon

@Mammon MathematicaScript is new in v8. What version do you have? – Warble

@Mammon It seems my assumption you were using MathematicaScript was wrong. In that case you should try $CommandLine. – Arronarrondissement

Congrats on 10k, Sjoerd! Welcome to the club of deleted crap viewers :) – Hairpiece

@yoda Thanks, and now the Mathematica gold badge, that'll impress my kids ;-) – Arronarrondissement

Answer 3

I'm fond of passing things in using environment variables:

http://reference.wolfram.com/mathematica/ref/Environment.html

Agonist

Helpful, but it's a bit more manual than specifying command line flags. – Mammon