running Mathematica script from the command line

description.md

Executing Mathematica Scripts Within the Command-Line

This guide will show how to run Wolfram Mathematica scripts right from the command-line, without using the Frontend.

Setting up the console environment (MacOS)

Technically, a Mathematica script can be executed from the command line using the Mathematica Kernel.

After installation of the Wolfram Mathematica application, default location of that executable kernel should be at /Applications/Mathematica.app/Contents/MacOS:

/Applications/Mathematica.app/Contents/MacOS
                                        ├── [  13]  MathKernel -> WolframKernel
                                        ├── [ 50M]  Mathematica
                                        ├── [  11]  MathematicaServer -> Mathematica
                                        ├── [196K]  WolframKernel
                                        ├── [  13]  wolfram -> WolframKernel
                                        └── [7.7M]  wolframscript

                                        1 directory, 6 files

Say there is a script test.m, then one would execute it via this command:

$ /Applications/Mathematica.app/Contents/MacOS/MathKernel -script test.m

ℹ️ A much easier approach would be to add the MacOS folder to the system's path:

export PATH=$PATH:/Applications/Mathematica.app/Contents/MacOS/

and also save this inside the ~/.zshrc file to have it each time the shell is started.

An alias can be created, such that the MathKernel -script prefix can be typed faster when executing the scripts.

export PATH=$PATH:/Applications/Mathematica.app/Contents/MacOS
alias math="MathKernel -script"

⚠️ When executing the MathKernel on any script file, make sure there are no running instances of other kernels. This means that any Frontend Mathematica applications should be closed. Check the process tree for active kernels. Otherwise the script execution will throw error about license/credentials:

basavyr@192 System-Differential-Equations % math linear_ode.m 
No valid password found.

Example of script that can be executed is this one.

(* solver for a linear ordinary differential equation *)

(* This script aims at solving Eq. (1) from https://mathinsight.org/ordinary_differential_equation_linear_integrating_factor*)

diffEq = f'[t] == Power[t, 2] - f[t];

sol = DSolve[diffEq, f[t], t]

(* make the constant from the sol term as a variable *)

solC[c_] :=
    Values @ sol[[1, 1]] /. {C[1] -> c};

Print["Solutions for f[t]"]

Export["c_values.pdf", ListPlot[Table[{t, solC[1]}, {t, -1, 10}], Joined
     -> True, PlotRange -> All, PlotStyle -> Red, PlotLabel -> "c=1", FrameLabel
     -> {"t", "f[t]"}, Frame -> True, ImageSize -> 400, PlotMarkers -> {Automatic,
     10}, Axes -> False, PlotRange -> All]]

currentWorkingDirectory = Directory[];

Print["Current working directory is: " <> currentWorkingDirectory]

initialDirectory = $InitialDirectory;

Print["The initial directory: ", initialDirectory]

(* change the current working directory one above*)

newWorkingDirectory = SetDirectory[ParentDirectory[currentWorkingDirectory
    ]];

Print["Current working directory is now: " <> newWorkingDirectory]

Print["The initial directory: ", initialDirectory]