Command line parameters and environment variables

Overview

When a program is started a user can give command line parameters and setup environment variables. For example the FreePascal compiler gets most of its parameters via command line options:

 fpc -Fudirectory -gh unit1.pas

Command line parameters

A pascal program can get access the parameters via ParamStr and ParamCount. ParamStr(0) is the program path itself. ParamStr(1) is the first parameter. ParamCount is the number of parameters.

<DELPHI> program Project1;

{$mode objfpc}{$H+}

var

 i: Integer;

begin

 writeln('Program: ',ParamStr(0));
 for i:=1 to ParamCount do
   writeln('Param ',i,': ',ParamStr(i));

end. </DELPHI>

For example:

 $ /tmp/project1 -a
 Program: /tmp/project1
 Param 1: -a