<p>First, I'm using Linux Mint 18.3 (Sylvia). Until now, I've been using OpenSCAD with the GUI and never experienced issues. Now I try to start OpenSCAD from the command line, but it always opens an empty file, even if a file with the specified name exists. </p>

<p>Since I have a rather big script, I'd like to generate the STL's via the CLI. Due to this error, I can not even do any tests for parameter passing.</p>

<p>What I'd like to do is to issue a command (flom the command line or in a shell script) that says "Set objectID to 1, render and export the result to stl".</p>

<p>Here is my M(N)WE:</p>

<pre><code>// test.scad

objectID = 2;


if (objectID == 1)  
difference(){  
    cylinder(d=20, h=50, center=true);  
    cylinder(d=16, h=50.2, center=true);      
}

else if (objectID == 2)  
difference(){  
    cube(50, center=true);  
    cube([35,35,70], center=true);  
}
</code></pre>

<p>Any help will greatly be appreciated.</p>

You can specify variable values from command line using:
```
openscad     ...\
             ... \
             [ -D var=val [..] ] \
             ... \
             ... \
             filename
```
See the
OpenSCAD Manual
.