I prefer recycle.exe from Frank P. Westlake. It provides a nice before and after status. (I've been using Frank's various utilities for well over ten years..)

C:\> recycle.exe /E /F
Recycle Bin: ALL
    Recycle Bin C:  44 items, 42,613,970 bytes.
    Recycle Bin D:   0 items, 0 bytes.
            Total:  44 items, 42,613,970 bytes.

Emptying Recycle Bin: ALL
    Recycle Bin C:   0 items, 0 bytes.
    Recycle Bin D:   0 items, 0 bytes.
            Total:   0 items, 0 bytes.

It also has many more uses and options (output listed is from /?).

Recycle all files and folders in C:\TEMP:
  RECYCLE C:\TEMP\*

List all DOC files which were recycled from any directory on the C: drive:
  RECYCLE /L C:\*.DOC

Restore all DOC files which were recycled from any directory on the C: drive:
  RECYCLE /U C:\*.DOC

Restore C:\temp\junk.txt to C:\docs\resume.txt:
  RECYCLE /U "C:\temp\junk.txt" "C:\docs\resume.txt"

Rename in place C:\etc\config.cfg to C:\archive\config.2007.cfg:
  RECYCLE /R "C:\etc\config.cfg" "C:\archive\config.2007.cfg"

You can use this PowerShell command.

Clear-RecycleBin -Force

Note: If you want a confirmation prompt, remove the -Force flag

nircmd lets you do that by typing

nircmd.exe emptybin

http://www.nirsoft.net/utils/nircmd-x64.zip
http://www.nirsoft.net/utils/nircmd.html

You can use a powershell script (this works for users with folder redirection as well to not have their recycle bins take up server storage space)

$Shell = New-Object -ComObject Shell.Application
$RecBin = $Shell.Namespace(0xA)
$RecBin.Items() | %{Remove-Item $_.Path -Recurse -Confirm:$false}

The above script is taken from here.

If you have windows 10 and powershell 5 there is the Clear-RecycleBin commandlet.

To use Clear-RecycleBin inside PowerShell without confirmation, you can use Clear-RecycleBin -Force. Official documentation can be found here

I use this powershell oneliner:

gci C:\`$recycle.bin -force | remove-item -recurse -force

Works for different drives than C:, too

To stealthily remove everything, try :

rd /s /q %systemdrive%\$Recycle.bin

I know I'm a little late to the party, but I thought I might contribute my subjectively more graceful solution.

I was looking for a script that would empty the Recycle Bin with an API call, rather than crudely deleting all files and folders from the filesystem. Having failed in my attempts to RecycleBinObject.InvokeVerb("Empty Recycle &Bin") (which apparently only works in XP or older), I stumbled upon discussions of using a function embedded in shell32.dll called SHEmptyRecycleBin() from a compiled language. I thought, hey, I can do that in PowerShell and wrap it in a batch script hybrid.

Save this with a .bat extension and run it to empty your Recycle Bin. Run it with a /y switch to skip the confirmation.

<# : batch portion (begins PowerShell multi-line comment block)
:: empty.bat -- http://stackoverflow.com/a/41195176/1683264

@echo off & setlocal

if /i "%~1"=="/y" goto empty

choice /n /m "Are you sure you want to empty the Recycle Bin? [y/n] "
if not errorlevel 2 goto empty
goto :EOF

:empty
powershell -noprofile "iex (${%~f0} | out-string)" && (
    echo Recycle Bin successfully emptied.
)
goto :EOF

: end batch / begin PowerShell chimera #>
Add-Type shell32 @'
    [DllImport("shell32.dll")]
    public static extern int SHEmptyRecycleBin(IntPtr hwnd, string pszRootPath,
        int dwFlags);
'@ -Namespace System

$SHERB_NOCONFIRMATION = 0x1
$SHERB_NOPROGRESSUI = 0x2
$SHERB_NOSOUND = 0x4

$dwFlags = $SHERB_NOCONFIRMATION
$res = [shell32]::SHEmptyRecycleBin([IntPtr]::Zero, $null, $dwFlags)

if ($res) { "Error 0x{0:x8}: {1}" -f $res,`
    (New-Object ComponentModel.Win32Exception($res)).Message }
exit $res

Here's a more complex version which first invokes SHQueryRecycleBin() to determine whether the bin is already empty prior to invoking SHEmptyRecycleBin(). For this one, I got rid of the choice confirmation and /y switch.

<# : batch portion (begins PowerShell multi-line comment block)
:: empty.bat -- http://stackoverflow.com/a/41195176/1683264

@echo off & setlocal
powershell -noprofile "iex (${%~f0} | out-string)"
goto :EOF

: end batch / begin PowerShell chimera #>
Add-Type @'

using System;
using System.Runtime.InteropServices;

namespace shell32 {
    public struct SHQUERYRBINFO {
        public Int32 cbSize; public UInt64 i64Size; public UInt64 i64NumItems;
    };

    public static class dll {
        [DllImport("shell32.dll")]
        public static extern int SHQueryRecycleBin(string pszRootPath,
            out SHQUERYRBINFO pSHQueryRBInfo);

        [DllImport("shell32.dll")]
        public static extern int SHEmptyRecycleBin(IntPtr hwnd, string pszRootPath,
            int dwFlags);
    }
}
'@

$rb = new-object shell32.SHQUERYRBINFO

# for Win 10 / PowerShell v5
try { $rb.cbSize = [Runtime.InteropServices.Marshal]::SizeOf($rb) }
# for Win 7 / PowerShell v2
catch { $rb.cbSize = [Runtime.InteropServices.Marshal]::SizeOf($rb.GetType()) }

[void][shell32.dll]::SHQueryRecycleBin($null, [ref]$rb)
"Current size of Recycle Bin: {0:N0} bytes" -f $rb.i64Size
"Recycle Bin contains {0:N0} item{1}." -f $rb.i64NumItems, ("s" * ($rb.i64NumItems -ne 1))

if (-not $rb.i64NumItems) { exit 0 }

$dwFlags = @{
    "SHERB_NOCONFIRMATION" = 0x1
    "SHERB_NOPROGRESSUI" = 0x2
    "SHERB_NOSOUND" = 0x4
}
$flags = $dwFlags.SHERB_NOCONFIRMATION
$res = [shell32.dll]::SHEmptyRecycleBin([IntPtr]::Zero, $null, $flags)

if ($res) { 
    write-host -f yellow ("Error 0x{0:x8}: {1}" -f $res,`
        (New-Object ComponentModel.Win32Exception($res)).Message)
} else {
    write-host "Recycle Bin successfully emptied." -f green
}
exit $res

while

rd /s /q %systemdrive%\$RECYCLE.BIN

will delete the $RECYCLE.BIN folder from the system drive, which is usually c:, one should consider deleting it from any other available partitions since there's an hidden $RECYCLE.BIN folder in any partition in local and external drives (but not in removable drives, like USB flash drive, which don't have a $RECYCLE.BIN folder). For example, I installed a program in d:, in order to delete the files it moved to the Recycle Bin I should run:

rd /s /q d:\$RECYCLE.BIN

More information available at Super User at Empty recycling bin from command line

i use these commands in a batch file to empty recycle bin:

del /q /s %systemdrive%\$Recycle.bin\*
for /d %%x in (%systemdrive%\$Recycle.bin\*) do @rd /s /q "%%x"

Yes, you can Make a Batch file with the following code:

cd \Desktop

echo $Shell = New-Object -ComObject Shell.Application >>FILENAME.ps1
echo $RecBin = $Shell.Namespace(0xA) >>FILENAME.ps1
echo $RecBin.Items() ^| %%{Remove-Item $_.Path -Recurse -Confirm:$false} >>FILENAME.ps1


REM The actual lines being writen are right, exept for the last one, the actual thigs being writen are "$RecBin.Items() | %{Remove-Item $_.Path -Recurse -Confirm:$false}"   
But since | and % screw things up, i had to make some changes.

Powershell.exe -executionpolicy remotesigned -File  C:\Desktop\FILENAME.ps1

This basically creates a powershell script that empties the trash in the \Desktop directory, then runs it.

I use EmptyRecycleBin.py python script

You will need to pip install winshell

#!python3

# Empty Windows Recycle Bin

import winshell

try:
    winshell.recycle_bin().empty(confirm=False, show_progress=True, sound=False)
    print("Recycle Bin emptied")

except:
    print('Recycle Bin is already empty')

You can change the Boolean False and True statements to either turn on or off the following: Confirm yes\no dialog, progress bar, sound effect.

If you don't use python, this one-liner for powershell is great.

I actually have it in EmptyRecycleBin.ps1, and use it in Git Bash.

Clear-RecycleBin -Force

Create cmd file with line:

for %%p in (C D E F G H I J K L M N O P Q R S T U V W X Y Z) do if exist "%%p:\$Recycle.Bin" rundll32.exe advpack.dll,DelNodeRunDLL32 "%%p:\$Recycle.Bin"

All of the answers are way too complicated. OP requested a way to do this from CMD.

Here you go (from cmd file):

powershell.exe /c "$(New-Object -ComObject Shell.Application).NameSpace(0xA).Items() | %%{Remove-Item $_.Path -Recurse -Confirm:$false"

And yes, it will update in explorer.