I copied my password to the clipboard! Can you delete it?

Question

Following the best security practices, I keep a plain text file with my passwords on my hard drive. In fact, I just copied and pasted one of them to access my PPCG account.

In a lucid moment, I decide that the password should better not remain in the clipboard after its use. Since this happens to me often, I could use a program to remove the clipboard contents.

Challenge

Write a program or function that deletes or overwrites any text contained in the clipboard, using a programming language of your choice.

Additional details:

• If your system has several clipboards, you can write the program for any one of them. The only requirement is that it must be possible for the user to copy and paste text using that clipboard.

• If your clipboard keeps a history of recent copied entries, assume the most recent entry.

• If your answer is specific to an operating system or clipboard, indicate it in the title of your post, together with the used language.

• The clipboard is guaranteed to contain text when your program is run. You can either delete the contents from the clipboard, or overwrite it with something else (not necessarily text). The only requirement is that after running the program, pasting from the clipboard will not produce the original text.

• If you choose to overwrite with some fixed or randomly chosen text, you can assume that the previous clipboard contents are different from that text, so the password is effectively removed. In other words, disregard the possibility that the filler text coincides with the password.

• The program should not have any side-effects like restarting the system, closing programs, shutting down the computer, or freezing it. After your program is run, the user should be able to keep using the computer as normal, only with the password removed from the clipboard. Also, standard loopholes are forbidden.

Shortest code in bytes wins.

Answer 1

PHP + PHP GTK 2.0, 24 bytes

This assumes you already have the PHP GTK extension loaded.

<?GtkClipboard::clear();

Documentation reference: http://gtk.php.net/manual/en/html/gtk/gtk.gtkclipboard.method.clear.html

Answer 2

Ruby, 11 bytes (Windows)

`echo|clip`

Runs the windows clip command to replace clipboard contents with "ECHO is on."

Answer 3

Julia - 13 bytes

clipboard("")

Answer 4

Clojure, 117 bytes

#(.setContents(.getSystemClipboard(java.awt.Toolkit/getDefaultToolkit))(java.awt.datatransfer.StringSelection."")nil)

Basically the Java answer. Gets the system clipboard, and sets it to an empty string.

AWT lets you do so many random things. It's so verbose though!

Unfortunately, trying to put an import in there adds about 30 bytes, so I need to fully qualify everything.

(defn clear-clipboard []
  (.setContents
      (.getSystemClipboard
        (java.awt.Toolkit/getDefaultToolkit))
      (java.awt.datatransfer.StringSelection. "")
      nil))

Answer 5

Racket, 61 bytes

Clears the secondary X11 clipboard, or the usual clipboard on other systems.

#lang racket/gui
(send the-clipboard set-clipboard-string""0)

Answer 6

VB.NET, 29 bytes

Sub F
Clipboard.Clear
End Sub

Saved 2 bytes thanks to @hvd

Answer 7

Linux shell (text console), 10 (or 6) bytes

gpm -k;gpm

gpm(8) is the daemon providing mouse control for the Linux text terminal (not X11). gpm -k tells the daemon to shut down, no further pasting will be possible.

It could be shortened to just

gpm -k

which shutdowns the daemon but does not restart it - but it cold be argued that this goes against the "user should be able to keep using the computer as normal" requirement.

Answer 8

Cygwin (bash), 10 bytes

w>/dev/cl*

In Linux everything is a file. Except the clipboard. That is part of a program. How impure! Thankfully when Windows became enlightened with true ttys and bash, it was not hindered by the ancient blotch X. On Windows you can use the clipboard as file, the way it was meant to be used. (Ignore that this is worse for golfing).

Needs the procps-np package for w. In other mintty terminals (git bash), ls could be used.

Answer 9

Red, 19 bytes

write-clipboard ""

writes a null string to the system clipboard

Answer 10

Rust (Windows), 128 bytes

#[link(name="user32")]extern"C"{fn OpenClipboard(h:u8);fn EmptyClipboard();}fn main(){unsafe{OpenClipboard(0);EmptyClipboard()}}

Calls some Windows API functions improperly, doesn't even close the clipboard afterwards:

#[link(name = "user32")]
extern "C" {
    fn OpenClipboard(h: u8);
    fn EmptyClipboard();
}
fn main() {
    unsafe {
        OpenClipboard(0);
        EmptyClipboard();
    }
}

Answer 11

APL (Dyalog APL) on Windows, 27 26 bytes

⎕A⎕WC'Clipboard'('Text'⎕A)

⎕A using the name "ABC...Z",

⎕WC Window Create a

'Clipboard' object with the

('Text'⎕A) "ABC...Z"

---

Alternative of same length, but empties the clipboard and doesn't leave behind a global clipboard object:

(⎕NEW⊂'Clipboard').Text←''

⎕NEW⊂'Clipboard' create a NEW clipboard object

(…).Text←'' and set its Text property to the empty string

Answer 12

AutoIt, 11 bytes

ClipPut("")

Fills the clipboard with an empty string.

Answer 13

Ruby 25 bytes (MacOS)

IO.popen("pbcopy","w"){}

Launches the MacOS/OS X pbcopy as a subprocess and clears the clipboard.

Answer 14

Tcl, 15 bytes.

Not the shortest but the most readable:

clipboard clear

note: must be executed with wish instead of tclsh

Answer 15

Java, 56 Bytes

javafx.scene.input.Clipboard.getSystemClipboard()::clear

It can be used with an functional interface (for example java.lang.Runnable) just like

()->javafx.scene.input.Clipboard.getSystemClipboard().clear()

which was accepted as a function on page 1.

Full example:

public class Test
{
    public static void main(String... args)
    {
        Runnable test1 = () -> javafx.scene.input.Clipboard.getSystemClipboard().clear();
        Runnable test2 = javafx.scene.input.Clipboard.getSystemClipboard()::clear;

        // both are valid Runnable Objects on which you can call the run()-Method to clear the clipboard
        test1.run();
        test2.run();
    }
}

Answer 16

Julia 29 bytes

InteractiveUtils.clipboard(9)

Answer 17

Perl 5 + Win32::Clipboard, 41 bytes

$CLIP=Win32::Clipboard();
$CLIP->Empty();

Try it online!

Answer 18

Windows 10, 2 keystrokes

Win + V Delete

Based on the excel answer, the Google Chrome answer, and the Notepad++ answer.

Opens Windows Clipboard (this must be enabled in settings) and deletes the current entry.

Answer 19

Java, 139 bytes

enum c{;static{java.awt.Toolkit.getDefaultToolkit().getSystemClipboard().setContents(new java.awt.datatransfer.StringSelection(""),null);}}

No one said that the program can't crash at the end.

Ungolfed version:

enum c {;
    static {
        java.awt.Toolkit.getDefaultToolkit().getSystemClipboard().setContents(new java.awt.datatransfer.StringSelection(""), null);
    }
}

Answer 20

MFC, 54 51

OpenClipboard(0);EmptyClipboard();CloseClipboard();

Perhaps the first MFC submission ever!

---

If inside a method of a CWnd derived class I can use CWnd::OpenClipboard() which implementation is

_AFXWIN_INLINE BOOL CWnd::OpenClipboard()
    { ASSERT(::IsWindow(m_hWnd)); return ::OpenClipboard(m_hWnd); }

and I don't have to supply a parameter to OpenClipboard. Then it becomes:

MFC, 50

OpenClipboard();EmptyClipboard();CloseClipboard();

Answer 21

AutoIt, 11 bytes

ClipPut("")

Pretty simple.

10 bytes

ClipPut(0)

Could save 1 byte by setting clipboard to "0"

Answer 22

Factor, 38 bytes

""clipboard get set-clipboard-contents

Answer 23

HTML 50 45 bytes

<x onclick=navigator.clipboard.writeText`x`>x

Click on the rendered letter x to copy x to the clipboard.

Answer 24

AutoHotkey, 12 bytes

A_Clipboard=

AutoHotkey allows direct reading and writing to the clibpoard via the A_Clipboard global, and allows writing an empty string to a variable with just =.

Answer 25

Swift 5.10 (macOS), 50 bytes

The AppKit framework (and, by extension, NSPasteboard) are macOS-only.

import AppKit
NSPasteboard.general.clearContents()

Yeah. Turns out NSPasteboard has a method dedicated for this purpose.

This uses less bytes than setString(_:forType:), even with closure tricks, since you have to set the data type beforehand. That's AppKit for you.