How can I pipe console output directly to Notepad?

From what I can tell, there is no way to directly pipe into Notepad.

However, you can pipe into clip and then paste in notepad, like so:

 diff file1.txt file2.txt | clip && notepad

Then just press Ctrl+V in Notepad.

Consider using Vim, or in your case gVim if you prefer a graphical environment.

You can then pipe into it with a single hyphen as an argument, which instructs Vim/gVim to read from standard input.

diff file1.txt file2.txt | gvim -

here's a short Windows program that does it properly (without clobbering the clipboard). It should be adaptable to PowerShell, and I might update this answer if I get the time, but you can also just use that program directly.

Well, how about PowerShell? No need to install another application. Unfortunately, you will need to create a script file somewhere in your PATH...

Short version you can use

If you create a batch file (e.g. ShowInNotepad.bat) with the following contents and place it in your PATH somewhere:

@echo off
clip
powershell -Command $process = Start-Process -PassThru notepad;$SW_SHOW = 5;$sig = '[DllImport("""user32.dll""")] public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);';Add-Type -MemberDefinition $sig -name NativeMethods -namespace Win32;[Win32.NativeMethods]::ShowWindow($process.Id, $SW_SHOW) ^| Out-Null;Add-Type -AssemblyName System.Windows.Forms;[System.Windows.Forms.SendKeys]::SendWait('^^V');

you can then just call echo blah | ShowInNotepad from anywhere!

Note that this does assume that you're using a recent-ish version of Windows (Vista+) and have not disabled PowerShell or uninstalled the .NET framework. In other words, a default Windows installation will work.

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Lengthy explanation and alternatives

The easiest way I can think of is to automate the paste (Ctrl+V) action. Which at least one other answer is already doing, but that one uses AHK - you might have better luck getting PowerShell to work in a locked-down corporate environment.

Let's get on with the script, yea?

#start notepad, get process object (to get pid later)
$process = Start-Process -PassThru notepad;

# activate Notepad window
# based on http://stackoverflow.com/a/4994020/1030702
# SW_SHOW activates and shows a window http://msdn.microsoft.com/en-us/library/windows/desktop/ms633548%28v=vs.85%29.aspx
$SW_SHOW = 5;
$sig = '[DllImport("user32.dll")] public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);';
Add-Type -MemberDefinition $sig -name NativeMethods -namespace Win32;
[Win32.NativeMethods]::ShowWindow($process.Id, $SW_SHOW) | Out-Null;

# send a "Ctrl+V" keystroke to the active window
# from http://stackoverflow.com/a/17851491/1030702
Add-Type -AssemblyName System.Windows.Forms;
[System.Windows.Forms.SendKeys]::SendWait('^V');

It's pretty straightforward, so I won't bother explaining the script more than the comments already do.

Usage

To use it, you just need to place the script in a .ps1 file (e.g. ShowInNotepad.ps1), place it somewhere in your PATH and then call powershell ShowInNotepad.ps1 after placing the text you want to display in the clipboard.

Example:

echo blah | clip && powershell ShowInNotepad.ps1

Unfortunately, executing PowerShell scripts can sometimes be difficult (execution policies and all). Therefore, I've condensed this script to a one-liner you can call directly from the Command Prompt, or even place into a batch file:

powershell -Command $process = Start-Process -PassThru notepad;$SW_SHOW = 5;$sig = '[DllImport("""user32.dll""")] public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);';Add-Type -MemberDefinition $sig -name NativeMethods -namespace Win32;[Win32.NativeMethods]::ShowWindow($process.Id, $SW_SHOW) ^| Out-Null;Add-Type -AssemblyName System.Windows.Forms;[System.Windows.Forms.SendKeys]::SendWait('^^V');

If you create a batch file (e.g. ShowInNotepad.bat) with the following contents and place it in your PATH somewhere:

@echo off
clip
powershell -Command $process = Start-Process -PassThru notepad;$SW_SHOW = 5;$sig = '[DllImport("""user32.dll""")] public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);';Add-Type -MemberDefinition $sig -name NativeMethods -namespace Win32;[Win32.NativeMethods]::ShowWindow($process.Id, $SW_SHOW) ^| Out-Null;Add-Type -AssemblyName System.Windows.Forms;[System.Windows.Forms.SendKeys]::SendWait('^^V');

you can then just call echo blah | ShowInNotepad from anywhere!