You should look at example 3 in the Help > Scripting Index > Functions>Run Program.
Attached is a script written for chapter 9 of JSL Companion, Applications of the JMP Scripting Languge, Second Edition. It includes multiple methods for reading multiple commands; multple commands to one program, or multiple DOS commands. See example #5 in this script for multiple dos commands (cd, dir, etc.) The discussion notes start on line 199 and the JSL is on line 253 to 287.
If you are just wanting to take notes, during your session, here is a simple script that does not require Run Program.
Names Default to Here(1);
noteslst ={};
InsertInto(noteslst, char(AsDate(Today()))|| " Notes");
InsertInto(noteslst, "Hello, World!");
InsertInto(noteslst,"It's hot here, 99 degrees");
InsertInto(noteslst,"Time to cool off");
InsertInto(noteslst,"Good Bye");
xtxt = Concat Items(noteslst,"\!N");
Save Text File( "c:\temp\July23Notes.txt" , xtxt);