edit your pastebin pastes with POWERSHELL (minimal | with comments)

#
#
#
# THIS IS THE VERY LEAST YOU NEED TO POST AN EDIT REQUEST TO PASTEBIN
# IF YOU DON'T WANT COMMENTS GO CHECK THE MINIMAL UN-COMMENTED VERSION:
# https://pastebin.com/zQjAMW8J
# MINIMAL FORM OF: "Pastebin | edit your PASTE with POWERSHELL" https://pastebin.com/N4YsJQiC
#
#
#
$ptboundary = 'AAAAAAAAAAOPTIMUMPRAIHUHUHAHA' # random text to separate the request's fields
$PASTE_ID = "N4YsJQiC" # your paste's url identifier (the final part of https://pastebin.com/N4YsJQiC)
$MY_NEW_TEXT = "YOUR TEXT GOES HERE" # your paste's final text
$COOKIE_VALUE = "YOUR COOKIE GOES HERE" # check your browser cookies and copy the 'pastebin-frontend' value



$session = New-Object Microsoft.PowerShell.Commands.WebRequestSession
$session.Cookies.Add((New-Object System.Net.Cookie(
    "pastebin-frontend",
    $COOKIE_VALUE,
    "/",
    "pastebin.com"
)))



# FIRST REQUEST TO GET THE csrf token (its neccesary to send the POST REQUEST of the /edit/ method)
$WR = Invoke-WebRequest `
-Uri "https://pastebin.com/edit/$PASTE_ID" `
-WebSession $session ` # this variable will change after the request!!



# SEARCHING AND SAVING THE csrf token
$csrf = ($WR.RawContent -split '\r?\n' | Select-String '^.*input.*?name="_csrf' -Raw) -replace '^.*value *= *"(.*?)".*$', '$1'



# HERE IS WHERE YOUR EDITED TEXT BELONGS
# POST REQUEST's string (to edit the paste)
$STRING = @(
    # SEPARATOR
    "--$ptboundary"
    # FIELD
    'Content-Disposition: form-data; name="_csrf-frontend"'
    ''
    $csrf # the csrf we got right before
    # SEPARATOR
    "--$ptboundary"
    # FIELD
    'Content-Disposition: form-data; name="PostForm[text]"'
    # THIS HAS TO BE BLANK (PROB LIKE A SEPARATOR FOR THE FIELD. IDK) (maybe like a : or =)
    ''
    # THIS IS THE FINAL TEXT OF THE PASTE
    # (IT CAN CONTAIN \n, \r, simbols or whatever)
    # 'MY TEXT' # COMMENTED SO YOU CAN CHANGE IT WITH A VARIABLE
    $MY_NEW_TEXT
    # SEPARATOR
    "--$ptboundary--"
) -join "`n" # join the fields and values with a newline


<#  It's hard to understand but your final string will form something like:
--AAAAAAAAAAOPTIMUMPRAIHUHUHAHA
Content-Disposition: form-data; name="_csrf-frontend"

Ei3ecOPvbg9BegRBTz48Zy8N8vUzwy_aniZUoCERJmuq8kfTkQPGIk31PUW8I_FoiclrI2MHSpsn0hYszpLSK6==
--AAAAAAAAAAOPTIMUMPRAIHUHUHAHA
Content-Disposition: form-data; name="PostForm[text]"

YOUR TEXT GOES HERE
--AAAAAAAAAAOPTIMUMPRAIHUHUHAHA--
#>
#
# that csrf token is a fake one.
#
# convert the string to bytes, for the request's body
$BYTES = ([System.Text.Encoding]::UTF8.GetBytes($STRING))



# send the post request to pastebin
Invoke-WebRequest -Method Post -Uri "https://pastebin.com/edit/$PASTE_ID" `
-WebSession $session `
-ContentType "multipart/form-data; boundary=$ptboundary" `
-Body $BYTES