How do I modify the PATH environment variable when running an Inno Setup Installer?

Question

Inno Setup lets you set environment variables via the [Registry] sections (by setting registry key which correspond to environment variable)

However, sometimes you d

Answer 1

You can use LegRoom.net's modpath.iss script in your InnoSetup script file:

#define MyTitleName "MyApp" 

[Setup]
ChangesEnvironment=yes

[CustomMessages]
AppAddPath=Add application directory to your environmental path (required)

[Files]
Source: "install\*"; DestDir: "{app}"; Flags: ignoreversion recursesubdirs createallsubdirs; 

[Icons]
Name: "{group}\{cm:UninstallProgram,{#MyTitleName}}"; Filename: "{uninstallexe}"; Comment: "Uninstalls {#MyTitleName}"
Name: "{group}\{#MyTitleName}"; Filename: "{app}\{#MyTitleName}.EXE"; WorkingDir: "{app}"; AppUserModelID: "{#MyTitleName}"; Comment: "Runs {#MyTitleName}"
Name: "{commondesktop}\{#MyTitleName}"; Filename: "{app}\{#MyTitleName}.EXE"; WorkingDir: "{app}"; AppUserModelID: "{#MyTitleName}"; Comment: "Runs {#MyTitleName}"

[Registry]
Root: HKLM; Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; ValueType: expandsz; ValueName: "Path"; ValueData: "{olddata};{app}"

[Tasks]
Name: modifypath; Description:{cm:AppAddPath};   

[Code]

const
    ModPathName = 'modifypath';
    ModPathType = 'system';

function ModPathDir(): TArrayOfString;
begin
    setArrayLength(Result, 1)
    Result[0] := ExpandConstant('{app}');
end;

#include "modpath.iss"