NSIS - printing to prompt during command line install

I'm making installers for windows using NSIS and have a number of custom install options that the user can specify using the command line, for example:

installer.exe /IDPATH=c:\Program Files\Adobe\Adobe InDesign CS5 /S

What I want to do is show these options to the p开发者_如何学Cerson installing. I can easily enough parse the /? or /help parameters with ${GetParameters} and ${GetOptions}, but how do I do the actual printing to the command prompt?

NSIS is a GUI program and does not really have the ability to write to stdout.

On XP and later you can do this with the system plugin:

System::Call 'kernel32::GetStdHandle(i -11)i.r0' 
System::Call 'kernel32::AttachConsole(i -1)' 
FileWrite $0 "hello" 

On < XP, there is no AttachConsole and you need to call AllocConsole on those systems (Will probably open a new console window)

Edit: You could open a new console if the parent process does not have one already with

!include LogicLib.nsh
System::Call 'kernel32::GetStdHandle(i -11)i.r0' 
System::Call 'kernel32::AttachConsole(i -1)i.r1' 
${If} $0 = 0
${OrIf} $1 = 0
 System::Call 'kernel32::AllocConsole()'
 System::Call 'kernel32::GetStdHandle(i -11)i.r0' 
${EndIf}
FileWrite $0 "hello$\n" 

But it does not really make any sense as far as /? handling goes, you might as well open a message box when there is no console

!include LogicLib.nsh
StrCpy $9 "USAGE: Hello world!!" ;the message
System::Call 'kernel32::GetStdHandle(i -11)i.r0' ;try to get stdout
System::Call 'kernel32::AttachConsole(i -1)i.r1' ;attach to parent console
${If} $0 <> 0
${AndIf} $1 <> 0
 FileWrite $0 "$9$\n" 
${Else}
 MessageBox mb_iconinformation $9
${EndIf}

!include LogicLib.nsh
StrCpy $9 "USAGE: Hello world!!" ;the message
System::Call 'kernel32::AttachConsole(i -1)i.r0' ;attach to parent console
${If} $0 != 0
 System::Call 'kernel32::GetStdHandle(i -11)i.r0' ;console attached -- get stdout
 FileWrite $0 "$9$\n" 
${Else}
 ;no console to attach -- show gui message
 MessageBox mb_iconinformation $9
${EndIf}

First attach console then get std handle. Before attach handles may (often will) be invalid.